Recombinant therapeutic FXN constructs and methods of treating friedreich ataxia and related conditions

Abstract

Recombinant human FXN constructs and related methods for treating Friedreich ataxia (FA), and related disorders in a subject are provided.

Description

[0001]Recombinant Therapeutic FXN Constructs and Methods of Treating Friedreich Ataxia and Related Conditions BACKGROUND Friedreich ataxia (FA) is a rare, inherited disorder that causes progressive damage to the nervous system. This can cause movement and sensory symptoms and trouble with walking and gait. In FA, nerve fibers in the spinal cord and peripheral nerves break down, becoming thinner. In the brain, the cerebellum, part of the brain that coordinates balance and movement, is most affected. FA affects a person’s peripheral nerves, which carry information back and forth from the brain to the body using sensory and motor signals. This is why a person with FA develops motor weakness and sensory loss. Symptoms typically begin between the ages of five and 15, although they sometimes appear after age 25. Symptoms of FA may include: ●Awkward, unsteady movements and impaired muscle coordination (ataxia) that worsensover time ●Difficulty walking and poor balance● Impaired sensory functions, such as loss of sensation in the arms and legs, which mayspread to the trunk and other parts of the body ●Loss of normal reflexes, especially in the knees and ankles● Slowness and slurring of speech (dysarthria)● Increased muscle tone (spasticity)● Curving of the spine to one side (scoliosis)● Difficulty swallowing● Hearing and vision loss● FatigueFA also may cause heart disease, specifically cardiomyopathy (a disease of cardiac muscle that may lead to heart failure or heart rhythm irregularities), and diabetes. Although rare, Friedreich ataxia is the most usual form of hereditary ataxia in the UnitedStates. Friedreich ataxia is caused by a defect (mutation) in a gene labeled FXN, which carries the genetic code for the production of a protein called frataxin. Frataxin is necessary for the proper function of the energy-producing part of a cell (called the mitochondria). In FA, an abnormal pattern in the DNA sequence of the protein (called a GAA triplet repeat) appears hundreds or more times, which greatly disrupts the normal production of frataxin. Research suggests that without a normal level of frataxin, certain cells in the body (especially peripheral nerve, spinal cord, brain, and heart muscle cells) produce energy less effectively and may have a buildup of toxic byproducts leading to what is called “oxidative stress.” Lack of normallevels of frataxin also may lead to increased levels of iron in the mitochondria. When the excessiron reacts with oxygen, free radicals can be produced. Although free radicals are essential molecules in the body metabolism, they can also destroy cells and harm the body. Individuals who inherit two defective copies of the FXN gene, one from each parent, will develop the disease. A person who inherits only one abnormal copy of the gene is called a carrier. A carrier will not develop the disease but could pass the gene mutation on to his or her children. This is called autosomal recessive inheritance. Genetic testing can determine if a person is a carrier of FA and whether they will pass FA along to any future children. There is a need in the field for an effective therapy for treating these disorders and restoringFXN production in those patients who have disease-causing FXN mutations.SUMMARY In an aspect, the present disclosure provides a therapeutic FXN polynucleotide construct comprising: a promoter fragment; an optional non mammalian based miRNA regulatory element and at least one cognate miRNA binding site; a human FXN coding sequence; a 3’ regulatory element; and a polyadenylation signal. In certain embodiments, the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NO:1 or SEQ ID NO:3, or a nucleotide sequence having at least 80%, 90%,95%, 96%, 97%, 98% or 99% identity to SEQ ID NO:1 or SEQ ID NO:3.In certain embodiments, the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NO:1 or SEQ ID NO:3, or a nucleotide sequence having at least 80% identity to SEQ ID NO:1 or SEQ ID NO:3. In certain embodiments, the polynucleotide construct encodes the amino acid sequence set forth in SEQ ID NO: 2.In certain embodiments, the promoter fragment comprises SEQ ID NO:7, SEQ IDNO:13, or SEQ ID NO:14 or a nucleotide sequence having at least 90%, 95%, 96%, 97%, 98%or 99% identity to any of SEQ ID NO:7, SEQ ID NO:13, or SEQ ID NO:14.In certain embodiments, the promoter fragment comprises SEQ ID NO:7, SEQ ID NO:13, or SEQ ID NO:14 or a nucleotide sequence having at least 90% identity to any of SEQ ID NO:7, SEQ ID NO:13, or SEQ ID NO:14. In certain embodiments, the 3’ regulatory element comprises woodchuck hepatitis virus post-transcriptional regulatory element (WPRE3) SEQ ID NO:9 or a nucleotide sequence havingat least 80%, 90%, 95%, 96%, 97%, 98% or 99% identity to SEQ ID NO: 9.In certain embodiments, the 3’ regulatory element comprises woodchuck hepatitis virus post-transcriptional regulatory element (WPRE3) SEQ ID NO:9 or a nucleotide sequence having at least 80% identity to SEQ ID NO: 9. In certain embodiments, the polynucleotide construct comprises SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12, or a nucleotide sequence having at least 90%, 95%, 96%, 97%, 98% or 99% identity to SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12. In certain embodiments, the polynucleotide construct comprises, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12, or a nucleotide sequence having at least 90% identity to SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12. In certain embodiments, the polynucleotide construct further comprises at least one adeno-associated virus (AAV) inverted terminal repeat (ITR). In certain embodiments, the polynucleotide construct comprises two AAV ITRs. In additional embodiments, the disclosure provides a vector comprising the polynucleotide construct of any of the embodiments described herein. In certain embodiments, the vector is a viral vector. In certain embodiments, the vector is an adeno-associated virus (AAV) vector. In certain embodiments, the AAV vector is an AAV9 vector. In another aspect, the present disclosure provides a recombinant adeno-associated virus(rAAV), comprising any of the polynucleotide constructs or vectors described herein. In certainembodiments, the rAAV is AAV9. In another aspect, the present disclosure provides a virion comprising the rAAV described herein. In another aspect, the present disclosure provides a transformed cell comprising any of thepolynucleotide constructs described herein, the vectors described herein, the rAAVs describedherein, or the virions described herein. In another aspect, the present disclosure provides a pharmaceutical compositioncomprising any of the polynucleotide constructs described herein, the vectors described herein, therAAVs described herein, or the virions described herein, and optionally, a pharmaceutically acceptable carrier. In another aspect, the present disclosure provides a method of treating Friedreich ataxia (FA), and / or an FA associated disorder in a subject, the method comprising administering to thesubject an effective amount of any of the polynucleotide constructs described herein, the vectorsdescribed herein, the rAAVs described herein, or the virions described herein, or the pharmaceutical compositions described herein. In another aspect, the present disclosure provides a method of increasing mitochondrial iron transport and or respiration in a subject diagnosed with FA, the method comprising administering to the subject an effective amount of any of the polynucleotide constructs described herein, the vectors described herein, the rAAVs described herein, the virions described herein, or the pharmaceutical compositions described herein. In certain embodiments, the administration is by intracerebral ventricular injection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration to the subject. In certain embodiments, administration does not result in an increase above baseline of anyone or more of the integrated stress response (ISR) markers: Atf4, Asns, Fgf21, Gdf15 or Trib3 incardiac or neuronal tissue. In another aspect, a polynucleotide construct described herein, a vector described herein, an rAAV described herein, a virion described herein, or a pharmaceutical composition described herein is provided for use in the treatment of Friedreich ataxia (FA), and / or an FA associated disorder in a subject. In certain embodiments, a polynucleotide construct described herein, a vector described herein, an rAAV described herein, a virion described herein, or a pharmaceutical composition described herein is administered to the subject by intracerebral ventricular injection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration. In another aspect, the disclosure provides use of any of the polynucleotide constructs described herein, the vectors described herein, the rAAVs described herein, the virions describedherein, or the pharmaceutical compositions described herein in the manufacture of a medicamentfor the treatment of Friedreich ataxia (FA), and / or an FA associated disorder in a subject. In certain embodiments, administration is by intracerebral ventricular injection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration. In certain embodiments, administration does not result in an increase above baseline of anyone or more of the integrated stress response (ISR) markers: Atf4, Asns, Fgf21, Gdf15 or Trib3 incardiac or neuronal tissue. In certain embodiments, the treatment results in an improvement in one or more symptoms associated with FA. In certain embodiments, the one or more symptoms associated with FA is selected from, awkward and unsteady movements, impaired muscle coordination, difficulty walking, poor balance, impaired sensory functions, loss of normal reflexes, dysarthria, spasticity, scoliosis, difficulty swallowing, hearing loss, vision loss, and fatigue, among others. In certain embodiments, the treatment results in improved motor function. In certain embodiments, the treatment results in improved cardiac function. In certain embodiments, treatment results in an increase of frataxin protein in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or 100% relative to frataxin expression in the subject prior to treatment.BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 shows a graph of flow cytometry data illustrating the effects of a therapeuticcassette (feed forward circuit) for tuning human frataxin (FXN) protein expression level. Reporter constructs, in which the reporter mNeonGreen is fused to hFXN and a second expression cassette allowing mRuby to be measured as a transfection control, were transfected into HEK cells and after 48 hrs cells were processed, analyzed by flow cytometry and levels of mRuby (transfection efficiency) and mNeonGreen (hFXN) were measured.Fig. 2 shows graphs of flow cytometry data illustrating the effects of adding intragenicintrons to the hFXN transgene sequence. Intron sequences comprise fragments of the respective human endogenous FXN introns 1 to 4. Fig. 3 shows maps depicting the elements of constructs SEQ ID NO: 4 (NG346; CBM- hFXN_in1-WPRE3-SV40pA), SEQ ID NO: 5 (NG347; CBM-EXACT1-hFXN_in1-WPRE3- SV40pA), SEQ ID NO: 6 (NG348; CBM-EXACT1-hFXN-WPRE3-SV40pA), SEQ ID NO:11(NG349; hFXNP882-hFXN_in1-hFXNpA1) and SEQ ID NO:12 (NG350; hFXNP882-EXACT1-hFXN_in1-hFXNpA1). Fig. 4 depicts the study plan used to assess expression of hFXN vectors AAV9-NG346-NG350. Fig. 5 shows vector biodistribution of AAV9-hFXN at 4 weeks post-injection, asmeasured by qPCR performed on DNA isolated from snap-frozen tissues (n=3 per group). Fig. 6 shows protein expression of frataxin (FXN) at 4 weeks post-injection, as measuredby western blot (n=3 per group). Data is normalized to levels of frataxin detected in AAV9- NG347-treated animals and presented as fold-change over this value. Fig.7 shows elevated Integrated Stress Response (ISR) markers in the hearts of AAV9- NG346-treated animals, as measured by qRT-PCR performed on total RNA isolated from snap-frozen heart tissue (n=3 per group). Data is normalized to levels of Atf4, Asns, Fgf21, Gdf15, andTrib3 detected in vehicle-treated animals and presented as fold-change over the levels in vehicle-treated controls. Fig. 8 shows vector biodistribution of AAV9-hFXN at 8 weeks post-injection, asmeasured by qPCR performed on DNA isolated from snap-frozen tissues (n=6 per group). Figs. 9A-C show aspects of protein expression of frataxin (FXN) at 8 weeks post-injection, as measured by western blot (n=6 per group). Data is normalized to levels of frataxindetected in AAV9-NG347-treated samples (FIG. 9A) and presented as fold-change over thisvalue. Western blot gel analysis (FIG. 9B) of mature frataxin in tissues collected 8 weeks post-injection. In cerebellum and heart (FIG. 9C), where endogenous levels of frataxin could bedetected, data is normalized to levels of frataxin detected in vehicle-treated animals and presented as fold-change over this value.Fig. 10 shows transgenic human FXN and endogenous mouse Fxn mRNA expression at8 weeks post-injection. LLOQ = Lower limit of quantificationFig. 11 shows no elevation of ISR markers in the hearts of AAV9-NG347, AAV9-NG348, AAV9-NG349 or AAV9-NG350 treated animals, as measured by qRT-PCR performed on total RNA isolated from snap-frozen heart tissue (n=6 per group). Data is normalized to levelsof Atf4, Asns, and Trib3 detected in vehicle-treated animals and presented as fold-change over thelevels in vehicle-treated controls. Fig. 12 depicts the study plan and treatment groups used to assess direct delivery offrataxin to the DCN. Fig. 13 shows vector DNA biodistribution levels at 3-week timepoint in cortex,cerebellum, heart and liver after intracerebroventricular (ICV) delivery of vehicle or AAV9-NG346 / NG347 at a dose of 1.0 × 1011vg / mouse. Results are presented as number of vector copies per diploid genome ±S.E.M. For each tissue, vector biodistribution across vector treatment groups is not significantly different (ns = not significant; two-way ANOVA). Group size numbers areshown in the figure legend.Fig. 14 shows ELISA quantification of frataxin protein levels at 3 weeks (3-weeks post-dosing) in cortex, cerebellum, heart and liver after ICV delivery of vehicle or NG346 / NG347 at a dose of 1.0 × 1011vg / mouse. Results are shown as absolute levels of frataxin as detected by mouse frataxin ELISA (WT + Vehicle group) or human frataxin ELISA (WT + test article treatment groups). Group size numbers are shown in the figure legend. Fig. 15 shows vector DNA biodistribution at 9-week timepoint in heart and liver after IVdelivery of vehicle or AAV9- NG347 at a dose of 1.0 × 1013 vg / kg or 1.0 × 1014 vg / kg. Results arepresented as number of vector copies per diploid genome ±S.E.M. Asterisk denotes statistically significant differences (p<0.05) between the two doses in each tissue, as determined by unpaired t-test. Group size numbers are shown in the figure legend. Fig. 16 shows ELISA quantification of frataxin protein levels at 9 weeks (4 weeks post-dosing) in heart and liver after intravenous (IV) delivery of vehicle or AAV9-NG347 at a dose of1.0 × 1013vg / kg or 1.0 × 1014vg / kg. For each tissue, results are shown as absolute levels of frataxin as detected by mouse frataxin ELISA (WT + Vehicle group) or human frataxin ELISA (WT + test article treatment groups). Group size numbers are shown in the figure legend. For each treatment group, the mean ±S.E.M. is shown. Fig. 17 shows the relative expression of ISR marker genes Asns, Atf4 and Trib3 at a 9-week timepoint in the heart after IV delivery of vehicle or AAV9-NG347 at a dose of 1.0 × 1013vg / kg or 1.0 × 1014vg / kg. For each gene, expression in each treatment group is shown relative to the WT + Vehicle control group ±S.E.M. Asterisks denotes statistically significant differences (*= p<0.05; *** = p<0.001) between the two doses in each tissue, as determined by two-wayANOVA; ns = non-significant. Group size numbers are shown in the figure legend. Fig. 18 is a schematic showing the efficacy study design in the MCK-knockout (MCK-KO) cardiac model of Friedreich’s Ataxia. Fig. 19 shows vector DNA biodistribution in the necropsy cohorts at 10-week timepoint(5 weeks post-dosing) in heart and liver after IV delivery of vehicle or AAV9-NG347 / NG349 / NG350 at a dose of 5.0 × 1013 vg / kg or 1.5 × 1014 vg / kg. Results are presented asnumber of vector copies per diploid genome ±S.E.M. (n=6 per group).Fig. 20 shows ELISA quantification of frataxin protein levels in the necropsy cohorts at10 weeks (5 weeks post-dosing) in heart and liver after IV delivery of vehicle or AAV9-NG347 / NG349 / NG350 at a dose of 5.0 × 1013 vg / kg or 1.5 × 1014 vg / kg. For each tissue, resultsare shown as absolute levels of frataxin as detected by mouse frataxin ELISA (vehicle treatment groups) or human frataxin ELISA (test article treatment groups). For each treatment group, themean ±S.E.M. is shown (n=6 per group).Fig. 21 shows representative images of DAB-mediated detection of frataxin (endogenousand transgenic) in mice from the necropsy cohorts, across all treatment groups (n=6 per group). LV = left ventricle; RV = right ventricle. Fig. 22 shows the cardiac hypertrophy phenotype in MCK-KO mice is ameliorated 5weeks after delivery of regulated AAV9-hFXN in the necropsy cohort (n=6 per group). Heartweights and body weights were measured at time of necropsy. Fig. 23 shows a survival curve to 30 weeks (study endpoint), following IV delivery ofvehicle or AAV9-NG347 / NG349 / NG350 at 5 weeks (n=10 per group). Figs. 24A-C shows the amelioration of cardiac phenotypes in MCK-KO mice treatedwith AAV9-NG347 / NG349 / NG350. (Fig. 24A) ejection fraction and (Fig. 24B) fractionalshortening were measured by echocardiogram (ECHO). (Fig. 24C) Left ventricle mass to bodymass ratio was measured by weighing tissues at time of necropsy. Fig. 25 shows vector DNA biodistribution levels at 9-week timepoint in cortex,cerebellum, brainstem, spinal cord, heart and liver after IV delivery of vehicle or AAV-PHP.eB- hFXN at a dose of 2.0 × 1013vg / kg. Results are presented as number of vector copies per diploid genome ±S.E.M. Asterisks denotes statistically significant differences between treatment groups in each tissue, as determined by two-way ANOVA (* = p<0.05; *** = p<0.001; **** = p<0.0001; ns = non-significant). Group size numbers are shown in the figure legend. Fig. 26 shows ELISA quantification of frataxin protein expression at 9 weeks (3-weekspost-dosing) in cortex, cerebellum, brainstem, spinal cord, heart and liver after IV delivery of vehicle or AAV-PHP.eB-hFXN at a dose of 2.0 × 1013vg / kg. For each tissue, results are shown as absolute levels of frataxin (ng / mg protein) ±S.E.M. as detected by mouse frataxin ELISA (WT + Vehicle group) or human frataxin ELISA (WT + test article treatment groups). Group size numbers are shown in the figure legend. Fig. 27 is a schematic showing the design of an efficacy study in the PV-KO CNS modelof Friedreich’s Ataxia. Fig. 28 shows the Neuroscore in PV-KO mice is partially ameliorated in a dose-dependent manner in mice treated with AAV-PHP.eB-NG347 (n=6 per group). Figs. 29A-B show average latency to fall in the rotarod test at 4, 9, 12 and 18 weeks ofage. Dose-dependent amelioration of motor phenotypes was observed in female (FIG. 29A) andmale (FIG. 29B) PV-KO mice treated with AAV-PHP.eB-NG347.Fig. 30 shows vector DNA biodistribution in all treatment groups at an 18-weektimepoint (13 weeks post-dosing) in cortex, cerebellum, liver, and quadriceps after IV delivery ofvehicle or AAV-PHP.eB-NG347 at a dose of 2.0 × 1012 vg / kg, 2.0 × 1013 vg / kg or 5.0 × 1013vg / kg. Results are presented as number of vector copies per diploid genome ±S.E.M. (n=6 pergroup) Fig. 31 shows ELISA quantification of frataxin protein levels in all treatment groups atan 18-week timepoint (13 weeks post-dosing) in cortex, cerebellum, liver and quadriceps after IVdelivery of vehicle or AAV-PHP.eB-NG347 at a dose of 2.0 × 1012 vg / kg, 2.0 × 1013 vg / kg or 5.0× 1013 vg / kg. For each tissue, results are shown as absolute levels of frataxin as detected by mouse frataxin ELISA (vehicle treatment groups) or human frataxin ELISA (test article treatmentgroups). For each treatment group, the mean ±S.E.M. is shown (n=6 per group).DETAILED DESCRIPTIONAs described herein, recombinant FXN polynucleotide constructs and rAAVs can be used as a gene therapy to treat FA or related disorders related to a reduction in expression or lack of fully functional frataxin. Additionally, in certain embodiments, constructs and rAAVs as described herein can be used as a gene therapy to increase mitochondrial iron transport and or respiration in a subject in need thereof. Methods of treatment include injecting any of the rAAV’s described herein into a subject in need thereof. One skilled in the art would understand the quantities needed to treat the subject, as it would depend on multiple factors including size, age, and gender of the subject. Human FXN is described in Gene ID:2395 (synonyms include: CYAY, FA, FARR, FRDA, and X25) and encodes a mitochondrial protein which belongs to the FRATAXIN family. The protein functions in regulating mitochondrial iron transport and respiration and is described in UniProtKB:Q16595. The expansion of the intronic trinucleotide repeat GAA from 8-33 repeatsto >90 repeats results in no frataxin expression from that allele. Two copies of an FXN allelecontaining an expanded allele results in FA. Alternative splicing results in multiple transcript variants. As described herein, a polynucleotide or gene encoding FXN can be any variant or a polynucleotide having at least 80% identity to SEQ ID NO: 1 or SEQ ID NO:3, which encodes a functional FXN protein. Definitions Unless otherwise defined, all technical and scientific terms used herein have the meaning commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The following terms have the meanings given: AAV “rep” and “cap” genes refer to polynucleotide sequences encoding replication and encapsidation proteins of adeno-associated virus. AAV rep and cap are referred to herein as AAV “packaging genes.” "AAV" is an abbreviation for adeno-associated virus and may be used to refer to the virus itself or modifications, derivatives, or pseudotypes thereof. The term covers all subtypes and both naturally occurring and recombinant forms, except where required otherwise. The abbreviation "rAAV" refers to recombinant adeno-associated virus. The term "AAV" includes AAV type 1 (AAV1), AAV type 2 (AAV2), AAV type 3 (AAV3), AAV type 4 (AAV4), AAV type 5 (AAV5),AAV type 6 (AAV6), AAV type 7 (AAV7), AAV type 8 (AAV 8), AAV type 9 (AAV9), avianAAV, bovine AAV, canine AAV, equine AAV, primate AAV, non-primate AAV, and ovine AAV, and modifications, derivatives, or pseudotypes thereof. "Primate AAV" refers to AAV that infect primates, "non-primate AAV" refers to AAV that infect non-primate mammals, "bovine AAV" refers to AAV that infect bovine mammals, etc. In some embodiments, the AAV particle is AAV1, AAV2, rAAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV 10, AAV11, AAV12, AAV13, AAV 14, AAV 15 and AAV 16, AAV.rh8, AAV.rh10, AAV.rh20, AAV.rh39, AAV.Rh74, AAV.RHM4-1, AAV.hu37, AAV.Anc80, AAV.Anc80L65, AAV.7m8, AAV.PHP.B, AAV2.5, AAV2tYF, AAV3B, AAV.LK03, AAV.HSC1, AAV.HSC2, AAV.HSC3, AAV.HSC4, AAV.HSC5, AAV.HSC6, AAV.HSC7, AAV.HSC8, AAV.HSC9, AAV.HSC10, AAV.HSC11, AAV.HSC12, AAV.HSC13, AAV.HSC14, AAV.HSC15, or AAV.HSC16. In some embodiments, the rAAV particle is a derivative, modification, or a pseudotype of AAV1, AAV2, rAAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV 10, AAV11, AAV 12, AAV 13, AAV 14, AAV 15 and AAV 16, AAV.rh8, AAV.rh10, AAV.rh20, AAV.rh39, AAV.Rh74, AAV.RHM4-1, AAV.hu37, AAV.Anc80, AAV.Anc80L65, AAV.7m8, AAV.PHP.B, AAV2.5, AAV2tYF, AAV3B, AAV.LK03, AAV.HSC1, AAV.HSC2, AAV.HSC3, AAV.HSC4, AAV.HSC5, AAV.HSC6, AAV.HSC7, AAV.HSC8, AAV.HSC9, AAV.HSC10, AAV.HSC11, AAV.HSC12, AAV.HSC13, AAV.HSC14, AAV.HSC15, or AAV.HSC16. The various serotypes of AAV are attractive for several reasons, most prominently that AAV is believed to be non-pathogenic, and that the wildtype virus can integrate its genome site- specifically into human chromosome 19 (Linden et al., 1996, Proc Natl Acad Sci USA 93:11288- 11294). The insertion site of AAV into the human genome is called AAVS1. Site-specific integration, as opposed to random integration, is believed to likely result in a predictable long-term expression profile. The genomic sequences of various serotypes of AAV, as well as the sequences of the native terminal repeats (TRs), Rep proteins, and capsid subunits are known in the art. Such sequences may be found in the literature or in public databases such as GenBank. See, e.g., GenBank Accession Numbers NC-002077 (AAV-1), AF063497 (AAV-1), NC-001401 (AAV-2), AF043303 (AAV-2), NC-001729 (AAV-3), NC-001829 (AAV-4), U89790 (AAV-4), NC-006152 (AAV-5), AF513851 (AAV-7), AF513852 (AAV-8), and NC-006261 (AAV-8); the disclosures of which are incorporated by reference herein. See also, e.g., Srivistava et al., 1983, J. Virology 45:555; Chiorini et al., 1998, J. Virology 71:6823; Chiorini et al., 1999, J. Virology 73: 1309; Bantel-Schaal et al., 1999, J. Virology 73:939; Xiao et al., 1999, J. Virology 73:3994; Muramatsu et al., 1996, Virology 221:208; Shade et al., 1986, J. Virol. 58:921; Gao et al., 2002, Proc. Nat. Acad. Sci. USA 99: 11854; Moris et al., 2004, Virology 33:375-383; international patent publications WO 00 / 28061, WO 99 / 61601, WO 98 / 11244; WO 2013 / 063379; WO 2014 / 194132; WO 2015 / 121501, and U.S. Pat. Nos.6,156,303 and 7,906,111. An “rAAV vector” as used herein refers to an AAV vector comprising a polynucleotide sequence not of AAV origin (i.e., a polynucleotide heterologous to AAV), typically a sequence ofinterest for the genetic transformation of a cell. In some embodiments, the heterologouspolynucleotide may be flanked by at least one, and sometimes by two, AAV inverted terminal repeat sequences (ITRs). The term rAAV vector encompasses both rAAV vector particles and rAAV vector plasmids. A rAAV vector may either be single-stranded (ssAAV) or self- complementary (scAAV). An “AAV virus” or “AAV viral particle” or “rAAV vector particle” refers to a viral particle composed of at least one AAV capsid protein (typically by all of the capsid proteins of a wild-type AAV) and an encapsidated polynucleotide rAAV vector. If the particle comprises a heterologous polynucleotide (i.e., a polynucleotide other than a wild-type AAV genome such as a transgene to be delivered to a mammalian cell), it is typically referred to as a “rAAV vector particle” or simply an “rAAV vector”. Thus, production of rAAV particle necessarily includes production of rAAV vector, as such a vector is contained within an rAAV particle. “Vector,” means a recombinant plasmid or virus that comprises a polynucleotide to be delivered into a host cell, either in vitro or in vivo. “Recombinant,” as used herein means that the vector, polynucleotide, polypeptide or cell is the product of various combinations of cloning, restriction or ligation steps (e.g. relating to a polynucleotide or polypeptide comprised therein), and / or other procedures that result in a construct that is distinct from a product found in nature. A recombinant virus or vector is a viral particle comprising a recombinant polynucleotide. The terms respectively include replicates of the original polynucleotide construct and progeny of the original virus construct. “Recombinant viral vector” means a recombinant polynucleotide vector comprising one or more heterologous sequences (i.e., polynucleotide sequence not of viral origin). "Recombinant", as applied to an AAV particle means that the AAV particle is the product of one or more procedures that result in an AAV particle construct that is distinct from an AAV particle in nature. “AAV Rep” means AAV replication proteins and analogs thereof. “AAV Cap” means AAV capsid proteins, VP1, VP2 and VP3 and analogs thereof. In wild type AAV virus, three capsid genes vp1, vp2 and vp3 overlap each other. See, Grieger andSamulski, 2005, J. Virol. 79(15):9933-9944. A single P40 promoter allows all three capsid proteinsto be expressed at a ratio of about 1:1:10, vp1, vp2, vp3, respectively, which complement with rAAV production. For the production of recombinant AAV vectors, desired ratio of VP1:VP2:VP3 is in the range of about 1:1:1 to about 1:1:100, preferably in the range of about 1:1:2 to about 1:1:50, more preferably in the range of about 1:1:5 to about 1:1:20. Although the desired ratio of VP1:VP2 is 1:1, the ratio range of VP1:VP2 could vary from 1:50 to 50:1. A comprehensive list and alignment of amino acid sequences of capsids of known AAV serotypes is provided by Marsic et al., 2014, Molecular Therapy 22(11):1900-1909, especially atsupplementary FIG. 1.For illustrative purposes only, wild type AAV2 comprises a small (20-25 nm) icosahedral virus capsid of AAV composed of three proteins (VP1, VP2, and VP3; a total of 60 capsid proteins comprises the AAV capsid) with overlapping sequences. The proteins VP1 (735 aa; Genbank Accession No. AAC03780), VP2 (598 aa; Genbank Accession No. AAC03778) and VP3 (533 aa; Genbank Accession No. AAC03779) exist in a 1:1:10 ratio in the capsid. That is, for AAVs, VP1 is the full-length protein and VP2 and VP3 are progressively shorter versions of VP1, with increasing truncation of the N-terminus relative to VP1. “AAV TR” means a palindromic terminal repeat sequence at or near the ends of the AAV genome, comprising mostly complementary, symmetrically arranged sequences, and includes analogs of native AAV TRs and analogs thereof. In the case of recombinant parvovirus vectors, the recombinant polynucleotide is flanked by at least one, preferably two, inverted terminal repeat sequences (ITRs). “Frataxin” is a protein that plays a crucial role in iron metabolism mitochondrial function.Frataxin is localized to the mitochondria where it is involved in maintaining mitochondrial stabilityand function. It helps protect mitochondria from oxidative stress and ensures proper assembly ofmitochondrial components. In patients with Friedrich’s Ataxia (FA), mutations in the gene encoding Frataxin results in a deficiency of Frataxin protein. Frataxin encompasses full-length frataxin and functional fragments thereof. For example, in some embodiments, frataxin comprises the sequence set forth in Genbank Accession Number NP_000135.2. As used herein, “FXN” refers to the gene encoding Frataxin protein. “FXN” used herein may also refer to a shortened version of the word “Frataxin.” Provided herein are FXN polynucleotide constructs delivered in an AAV resulting in the expression of the mature Frataxin protein in a subject with FA. FXN encompasses the full-length gene and functional fragmentsthereof. For example, in some embodiments, FXN comprises the sequence set forth in GenbankAccession Number NM_000144.5.“Cis-motifs” includes conserved sequences such as found at or close to the termini of the genomic sequence and recognized for initiation of replication; cryptic promoters or sequences at internal positions likely used for transcription initiation, splicing or termination. “Therapeutically effective amount” means a minimal amount of active agent which is necessary to impart therapeutic benefit to a subject. For example, a “therapeutically effective amount” to a patient is such an amount which induces, ameliorates, stabilizes, slows down the progression or otherwise causes an improvement in the pathological symptoms, disease progression or physiological conditions associated with or resistance to succumbing to a disorder. “Gene” means a polynucleotide containing at least one open reading frame that is capable of encoding a particular polypeptide or protein after being transcribed and translated. “Coding sequence” means a sequence which encodes a particular protein” or “encoding nucleic acid”, denotes a nucleic acid sequence which is transcribed (in the case of DNA) and translated (in the case of mRNA) into a polypeptide in vitro or in vivo when placed under the control of (operably linked to) appropriate regulatory sequences. The boundaries of the codingsequence are determined by a start codon at the 5′ (amino) terminus and a translation stop codonat the 3′ (carboxy) terminus. A coding sequence can include, but is not limited to, cDNA from prokaryotic or eukaryotic mRNA, genomic DNA sequences from prokaryotic or eukaryotic DNA, and even synthetic DNA sequences. “Chimeric” means, with respect to a viral capsid or particle, that the capsid or particle includes sequences from different parvoviruses, preferably different AAV serotypes, as described in Rabinowitz et al., U.S. Pat. No.6,491,907, the disclosure of which is incorporated in its entirety herein by reference. See also Rabinowitz et al., 2004, J. Virol. 78(9):4421-4432. A particularly preferred chimeric viral capsid is the AAV2.5 capsid, which has the sequence of the AAV2 capsid with the following mutations: 263 Q to A; 265 insertion T; 705 N to A; 708 V to A; and 716 T to N. wherein the nucleotide sequence encoding such capsid is defined as SEQ ID NO: 15 as described in WO 2006 / 066066. Other preferred chimeric AAVs include, but are not limited to, AAV2i8 described in WO 2010 / 093784, AAV2G9 and AAV8G9 described in WO 2014 / 144229, and AAV9.45 (Pulicherla et al., 2011, Molecular Therapy 19(6):1070-1078). “Flanked,” with respect to a sequence that is flanked by other elements, indicates thepresence of one or more of the flanking elements upstream and / or downstream, i.e., 5′ and / or 3′,relative to the sequence. The term “flanked” is not intended to indicate that the sequences are necessarily contiguous. For example, there may be intervening sequences between the nucleic acid encoding the transgene and a flanking element. A sequence (e.g., a transgene) that is “flanked” by two other elements (e.g., TRs), indicates that one element is located 5′ to the sequence and the other is located 3′ to the sequence; however, there may be intervening sequences there between. “Polynucleotide” means a sequence of nucleotides connected by phosphodiester linkages. Polynucleotides are presented herein in the direction from the 5′ to the 3′ direction. A polynucleotide of the present invention can be a deoxyribonucleic acid (DNA) molecule or ribonucleic acid (RNA) molecule. Where a polynucleotide is a DNA molecule, that molecule can be a gene or a cDNA molecule. Nucleotide bases are indicated herein by a single letter code: adenine (A), guanine (G), thymine (T), cytosine (C), inosine (I) and uracil (U). A polynucleotide of the present invention can be prepared using standard techniques well known to one of skill in the art. “Transduction” of a cell by a virus means that there is transfer of a nucleic acid from the virus particle to the cell. “Transfection” of a cell means that genetic material is introduced into a cell for the purpose of genetically modifying the cell. Transfection can be accomplished by a variety of means known in the art, such as calcium phosphate, polyethyleneimine, electroporation, and the like. “Polypeptide” encompasses both peptides and proteins, unless indicated otherwise. “Gene transfer” or “gene delivery” refers to methods or systems for reliably inserting foreign DNA into host cells. Such methods can result in transient expression of non-integrated transferred DNA, extrachromosomal replication and expression of transferred replicons (e.g. episomes), or integration of transferred genetic material into the genomic DNA of host cells. “Transgene” is used to mean any heterologous nucleotide sequence incorporated in a vector, including a viral vector, for delivery to and including expression in a target cell (also referred to herein as a “host cell”), and associated expression control sequences, such as promoters. It is appreciated by those of skill in the art that expression control sequences will be selected based on ability to promote expression of the transgene in the target cell. An example of a transgene is a nucleic acid encoding a therapeutic polypeptide. The term "cell culture," refers to cells grown adherent or in suspension, bioreactors, roller bottles, hyperstacks, microspheres, macrospheres, flasks and the like, as well as the components of the supernatant or suspension itself, including but not limited to rAAV particles, cells, cell debris, cellular contaminants, colloidal particles, biomolecules, host cell proteins, nucleic acids, and lipids, and flocculants. Large scale approaches, such as bioreactors, including suspensioncultures and adherent cells growing attached to microcarriers or macrocarriers in stirredbioreactors, are also encompassed by the term "cell culture." Cell culture procedures for both large and small-scale production of proteins are encompassed by the present disclosure. The terms "purifying", "purification", "separate", "separating", "separation", "isolate", "isolating", or "isolation", as used herein, refer to increasing the degree of purity of rAAV particles from a sample comprising the target product and one or more impurities. Typically, the degree of purity of the target product is increased by removing (completely or partially) at least one impurity from the sample. In some embodiments, the degree of purity of the rAAV in a sample is increased by removing (completely or partially) one or more impurities from the sample by using a method described herein. “Homologous” used in reference to peptides, refers to amino acid sequence similarity between two peptides. When an amino acid position in both of the peptides is occupied by identical amino acids, they are homologous at that position. Thus, by “substantially homologous” means an amino acid sequence that is largely, but not entirely, homologous, and which retains most or all of the activity as the sequence to which it is homologous. As used herein, “substantially homologous” as used herein means that a sequence is at least 50% identical, and preferably at least 75% and more preferably 95% homology to the reference peptide. Additional peptide sequence modifications can be included, such as minor variations,deletions, substitutions, or derivatization of the amino acid sequence of the sequences disclosedherein, so long as the peptide has substantially the same activity or function as the unmodified peptides. Derivatives of an amino acid may include but not limited to trifluoroleucine, hexafluoroleucine, 5,5,5-trifluoroisoleucine, 4,4,4-trifluorovaline, p-fluorophenylaline, o- fluorotyrosine, m-fluorotyrosine, 2,3-difluorotyrosine, 4-fluorohistidine, 2-fluorohistidine, 2,4- difluorohistidine, fluoroproline, difluoroproline, 4-hydroxyproline, selenomethionine, telluromethionine, selenocysteine, selenatryptophans, 4-aminotryptophan, 5-aminotryptophan, 5- hydroxytryptophan, 7-azatryptophan, 4-fluorotryptophan, 5-fluorotryptophan, 6-fluorotryptophan, homoallylglycine, homopropargylglycine, 2-butynylglycine, cis-crotylglycine, allylglycine, dehydroleucine, dehydroproline, 2-amino-3-methyl-4-pentenoic acid, azidohomoalanine, asidoalanine, azidonorleucine, p-ethynylphenylalanine, p-azidophenylalanine, p- bromophenylalanine, p-acetylphenylalanine and benzofuranylalanine. Notably, a modified peptide will retain activity or function associated with the unmodified peptide, the modified peptide will generally have an amino acid sequence “substantially homologous” with the amino acid sequence of the unmodified sequence. Recombinant FXN In some embodiments, provided herein are recombinant human FXN constructs.Additional embodiments provided herein include nucleic acid constructs, such as vectors, which include as part of their sequence a recombinant human FXN. For example, aspects of the inventioninclude plasmids and / or other vectors that include the recombinant human FXN sequence alongwith other elements, such as regulatory elements. Further, the invention provides packaged genedelivery vehicles, such as a viral capsid, including recombinant human FXN sequence.Aspects of the invention also include methods of delivery and, preferably, expressing the recombinant human FXN gene by delivering the wild type or modified FXN sequence into a cellalong with elements required to promote expression in the cell. In certain embodiments, therecombinant FXN construct includes a non-mammalian-based miRNA “feed forward” regulatory element and at least one cognate miRNA binding site. Such a regulatory element, also described as a unique, non-naturally occurring miRNA sequence referred to as “EXACT or EXACT 1” is described for example, in WO2022 / 003348. In certain embodiments, the miRNA is non mammalian miRNA derived from an insect miRNA, optionally firefly luciferase. In certainembodiments, the insect miRNA is capable of specifically binding to firefly luciferase (fflux)miRNA binding site (i.e. the cognate binding site). In certain embodiments, there are a plurality ofmiRNA binding sites provided in the construct, optionally three miRNA binding sites, or optionally at least four miRNA binding sites, or optionally at least five miRNA binding sites, oroptionally at least six miRNA binding sites.Embodiments of the invention also provide gene therapy methods in which therecombinant human FXN gene sequence is administered to a subject, e.g., as a component of avector and / or packaged as a component of a viral gene delivery vehicle. Particular embodiments include those wherein the recombinant human FXN sequence has an identity of 75% to SEQ IDNO: 1 or SEQ ID NO: 3. In certain embodiments the recombinant human FXN sequence exhibitsgreater than 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or 99% identity with SEQ ID NO: 1 or SEQ ID NO:3.Recombinant FXN DesignsThe human FXN gene encodes the frataxin protein which is 210 amino acids in length. In certain recombinant FXN construct designs, expression of the transgene is driven by anendogenous promoter and the transcript stabilized with the WPRE3 (woodchuck hepatitis viruspost-transcriptional regulatory element 3) and SV40 polyadenylation signal. Exemplary sequences and potential therapeutic constructs are described in SEQ ID NOs: 5-6 and SEQ ID NOs: 11-12.Recombinant FXN construct designs are depicted in FIG.3. In some embodiments, the therapeuticis one or more of the constructs depicted in FIG.3. In some embodiments, the recombinant construct comprises a wild-type human or modified FXN nucleic acid sequence encoding frataxin. In certain recombinant FXN construct designs, expression of the transgene is driven by astrong, constitutive promoter CBh (Cytomegalovirus enhancer, Chicken Beta Actin promoter), and the transcript is stabilized with the ubiquitous polyadenylation signal bGHpA (bovine growth hormone polyadenylation signal). In certain recombinant FXN construct designs, expression of the transgene is stabilized with an endogenous human FXN 3’ UTR, and optionally an SV40pA. Modified Nucleic Acid for Expression of FXN In certain embodiments, the coding sequences for FXN may be optimized, or codon optimized as described below. “Optimized” or “codon-optimized” as referred to interchangeably herein, refer to a coding sequence that has been optimized relative to a wild type coding sequence (e.g., a coding sequence for FXN) to increase expression of the coding sequence, e.g., by minimizing usage of rare codons, decreasing the number of CpG dinucleotides, removing cryptic splice donor or acceptor sites, removing Kozak sequences, removing ribosomal entry sites, and the like. “Codon adaptation index” refers to the adaptation of a codon from a tRNA codon thatrarely occurs within the given organism or cell to a tRNA that occurs more often within the given organism or cell. A non-limiting example in which the codon adaptation index is calculated is byusing the “GenScript Rare Codon Analysis Tool.” (see Fan, K., Li, Y., Chen, Z. et al. GenRCA: auser-friendly rare codon analysis tool for comprehensive evaluation of codon usage preferencesbased on coding sequences in genomes. BMC Bioinformatics 25, 309 (2024).https: / / doi.org / 10.1186 / s12859-024-05934-z). “Percentage identity” refers to the numerical score of two given polynucleotides and / or polypeptides that have identical nucleic and / or amino acids within the same position as given by atypical sequence alignment program (i.e., BLAST methods). Codon Optimization There are sixty-four different codons. Sixty-one of them encode the twenty standard amino acids, while another three function as stop codons. The greater number of codons relative to the number of amino acids they code for, means that a single amino acid can be encoded by more than one codon. Indeed, some common amino acids, such as arginine and leucine, are encoded by as many as 6 codons. Different organisms exhibit bias towards use of certain codons over others for the same amino acid. Some species are known to avoid certain codons almost entirely. Such biases may affect protein expression. Therefore, it is important to consider codon optimization when designing gene therapy constructs. While numerous factors contribute to the success of protein expression, codon optimization plays a critical role, particularly when proteins are expressed in a heterologous system. As anexample, if a human gene is to be expressed in E. coli, choosing codons preferentially used by thebacterium can increase the success of protein expression. This is particularly true when rare codons are eliminated. Codon Adaptation Index One option for analyzing codon usage bias is the technique codon adaptation index (CAI).It calculates an index to tell how a “foreign” sequence will adapt to the host protein expressionmachinery. CAI compares the codon usage in the GOI to the most frequent codon usage in a set of highly expressed genes in the model expression organism. The relative adaptiveness of codons ranges from 0 to 1, depending on how the GOI is to the reference set of highly expressed gene sequences, with 1 being the closest. Examples of reference codon usages are contained in various databases, including the codon usage database kazusa.or.jp / codon / . Sequence Modification Examples of modifications include elimination of one or more cis-acting motifs and introduction of one or more Kozak sequences. In one embodiment, one or more cis-acting motifs are eliminated and one Kozak sequence is introduced. Examples of cis acting motifs that may be eliminated include internal TATA-boxes; chi- sites; ribosomal entry sites; ARE, INS, and / or CRS sequence elements; repeat sequences and / or RNA secondary structures; (cryptic) splice donor and / or acceptor sites, branch points; andrestriction sites, (e.g., Sall).Additionally, in certain embodiments, the codon adaptation index of the modified nucleicacid encoding FXN (i.e., the modified FXN gene) is preferably at least 0.74, preferably, at least0.76, even more preferably, at least 0.77, yet more preferably, at least 0.80, preferably, at least 0.82, more preferably, at least 0.84, yet more preferably, at least 0.85, even more preferably, at least 0.89, yet more preferably, at least 0.90, and most preferably, at least 0.91. In another embodiment the modified FXN sequence has a reduced level of CpGdinucleotides that being a reduction of about 10%, 20%, 30%, 50% or more, compared with thewild-type nucleic acid sequence encoding FXN (e.g., SEQ ID NO:1 or SEQ ID NO:3).It is known that methylation of CpG dinucleotides plays a key role in the regulation of geneexpression in eukaryotes. Specifically, methylation of CpG dinucleotides in eukaryotes essentially serves to silence gene expression through interfering with the transcriptional machinery. As such, because of the gene silencing evoked by methylation of CpG motifs, the nucleic acids and vectors of certain embodiments having a reduced number of CpG dinucleotides will provide for high and long-lasting transgene expression level, and potentially less risk of host / subject immunological response and / or toxicity. In one embodiment, the modified recombinant human FXN gene comprises fewer potentialCpG dinucleotides than wild type FXN gene.In certain embodiments, the recombinant human FXN gene sequence may also includeflanking restriction sites to facilitate subcloning into expression vector. Many such restriction sites are well known in the art. The disclosure includes a nucleic acid vector including the recombinant human FXN genesequence and various regulatory or control elements. The precise nature of regulatory elements useful for gene expression will vary from organism to organism and from cell type to cell type. In general, they include a promoter which directs the initiation of RNA transcription in the cell of interest. The terms “promoter” and “promoter fragment” are used interchangeably herein. The promoter may be constitutive or regulated. Constitutive promoters are those which cause an operably linked gene to be expressed essentially at all times. Regulated promoters are those which can be activated or deactivated. Regulated promoters include inducible promoters, which are usually “off” but which may be induced to turn “on,” and “repressible” promoters, which are usually “on” but may be turned “off.” Many different regulators are known, including temperature, hormones, cytokines, heavy metals and regulatory proteins. The distinctions are not absolute; a constitutive promoter may often be regulated to some degree. In some cases, an endogenous pathway may be utilized to provide regulation of the transgene expression, e.g., using a promoter that is naturally downregulated when the pathological condition improves. Examples of suitable promoters include adenoviral promoters, such as the adenoviral major late promoter; heterologous promoters, such as the cytomegalovirus (CMV) promoter; the respiratory syncytial virus promoter; the Rous Sarcoma Virus (RSV) promoter; the albumin promoter; inducible promoters, such as the Mouse Mammary Tumor Virus (MMTV) promoter; the metallothionein promoter; heat shock promoters; the α-1-antitrypsin promoter; the hepatitis B surface antigen promoter; the transferrin promoter; the apolipoprotein A-1 promoter; chicken beta- actin (CBA) promoter, the CBh promoter, and the CAG promoter (cytomegalovirus early enhancer element and the promoter, the first exon, and the first intron of chicken beta-actin gene and thesplice acceptor of the rabbit beta-globin gene) (Alexopoulou et al., 2008, BioMed. Central CellBiol. 9:2), and human FXN promoters. The promoter may be a tissue-specific promoter, such asthe mouse albumin promoter, which is active in liver cells as well as the transthyretin promoter (TTR). The promoter may be muscle specific promoter, such as the muscle creatine kinase (MCK) promoters (e.g., tMCK). In certain embodiments, muscle specific promoters can be used. It will be clear to one skilled in the art how to utilize and adapt any of these features as described herein. In another aspect, the recombinant human FXN construct further comprises an enhancer toincrease expression of the protein. Many enhancers are known in the art, including, but not limited to, the cytomegalovirus major immediate-early enhancer. More specifically, the CMV MIE promoter comprises three regions: the modulator, the unique region and the enhancer (Isomura and Stinski, 2003, J. Virol. 77(6):3602-3614). The CMV enhancer region can be combined with other promoters, or a portion thereof, to form hybrid promoters to further increase expression of anucleic acid operably linked thereto. For example, a chicken beta-actin (CBA) promoter, or aportion thereof, can be combined with the CMV promoter / enhancer, or a portion thereof, and a hybrid intron of chicken beta-actin (CBA) and minute virus of mice (MMV) introns to make a version of CBA termed the “CBh” promoter, which stands for chicken beta-actin hybrid promoter, as described in Gray et al. (2011, Human Gene Therapy 22:1143-1153). Introns can also be used to increase efficiency in mammalian expression vectors. Examples of introns are murine cytomegalovirus (MCMV) immediate early (IE) promoter, human cytomegalovirus (HCMV) immediate early (IE) promoter, and human elongation factor one alpha (EF-1 alpha) promoter. The intron can be varied depending on the gene of interest. Further, the control elements can include a collagen stabilization sequence (CSS), a stop codon, a termination sequence, and a poly-adenylation signal sequence, such as, but not limited to a bovine growth hormone poly A signal sequence (bGHpA), or SV40 poly A signal sequence (SV40pA) to drive efficient addition of a poly-adenosine “tail” at the 3′ end of a eukaryotic mRNA (see, e.g., Goodwin and Rottman, 1992, J. Biol. Chem.267(23):16330-16334). In some embodiments, the recombinant construct comprises an endogenous fragment of the human 3’UTR and polyadenylation sequence. In particular embodiments, the recombinant construct comprises a WPRE3 (SEQ ID NO:9) and SV40 polyadenylation sequence (SEQ ID NO: 10). The poly-A tail is a long chain of adenine nucleotides that is added to a messenger RNA (mRNA) molecule during RNA processing to increase the stability of the molecule. Similar to what happens in vivo. The poly-A tail makes the RNA molecule more stable and prevents its degradation. Additionally, the poly-A tail allows the mature messenger RNA molecule to be exported from the nucleus and translated into a protein by ribosomes in the cytoplasm. The woodchuck hepatitis virus post-transcriptional regulatory element (WPRE) increases transgene expression from a variety of viral vectors. WPRE is most effective when placed downstream of the transgene, proximal to the polyadenylation signal. It is possible that WPRE reduces viral mRNA readthrough transcription by improving transcript termination, which in turnwould increase viral titers and expression. (Gene Therapy volume 14, pages 1298–1304 (2007)).In some embodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 1 mismatch. In some embodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 2 mismatches. In some embodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16, wherein one or moreof SEQ ID NOs: 1-16 comprises 3 mismatches. In some embodiments, the FXN polynucleotideconstruct comprises one or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 4 mismatches. In some embodiments, the FXN polynucleotide construct comprisesone or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 5mismatches. In some embodiments, the FXN polynucleotide construct comprises one or more ofSEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 6 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises 7 mismatches. In some embodiments, theFXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16, wherein one or moreof SEQ ID NOs: 1-16 comprises 8 mismatches. In some embodiments, the FXN polynucleotideconstruct comprises one or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 9 mismatches. In some embodiments, the FXN polynucleotide construct comprisesone or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises 10 mismatches. In some embodiments, the FXN polynucleotide construct comprises one or more of SEQID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises no more than 1 mismatch. Insome embodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16, wherein one or more of SEQ ID NOs: 1-16 comprises no more than 2 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 3 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 4 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 5 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 6 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 7 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 8 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 9 mismatches. In someembodiments, the FXN polynucleotide construct comprises one or more of SEQ ID NOs: 1-16,wherein one or more of SEQ ID NOs: 1-16 comprises no more than 10 mismatches.Regulation of Expression The disclosure provides gene therapy constructs to treat Friedreich Ataxia (FA) designed to express constrained levels of wild-type human frataxin, regulated either by an EXACT circuit, endogenous FXN regulatory elements, or both (see Example 1). Feed-forward control of dosage sensitivity can be achieved in the dosage sensitive FXN gene using the non-mammalian EXACT mechanism (as described in WO / 2022 / 003348). Many genes are highly dosage sensitive whereby too little or too much expression of a gene product can have deleterious effects. Viral-mediated gene transfer is a powerful means to deliver therapeutic transgenes to target tissues and cells including cells of the nervous system. High virus titers are typically necessary to enable effective system-wide transduction for maximal therapeutic impact. However, the same high titers may cause overexpression toxicity due to supraphysiological levels of transgene expression achieved in some cells. An effective system is required to limit the expression of the vector-derived transgene within a window that alleviates the disease-causing genetic deficiency without producing overexpression toxicity. The EXACT mechanism limits the expression of a vector-derived transgene within awindow that alleviates the disease-causing genetic deficiency without producing overexpression toxicity. That is, the vector-derived transgene is downregulated at high vector dosages so that the circuit maintains a relatively stable level of expression across a range of vector doses with the result being that the overall population of cells express a more even and controlled level of vector- derived transgene. Increasing doses of vector will result in more cells expressing the transgene within a cell population but without a concomitant increase in overexpression compared to conventional gene therapy cassettes. Sensitive cell types that often receive high vector loads suchas in the heart, liver and dorsal root ganglia will also be less susceptible to superinfection-mediatedoverexpression by this mechanism. In some embodiments, certain FXN polynucleotide constructs described herein are regulated by an EXACT circuit. In some embodiments, certain FXN polynucleotide constructsdescribed herein are regulated by endogenous FXN regulatory elements. In some embodiments,certain FXN polynucleotide constructs described herein are regulated by an EXACT circuit and endogenous FXN regulatory elements. Non-viral vectors In a particular embodiment, the vector used according to the invention is a non-viral vector. Typically, the non-viral vector may be a plasmid which includes nucleic acid sequences containingrecombinant human FXN, or variants thereof.Packaged Recombinant FXN SequenceThe recombinant human FXN gene sequence may also be provided as a component of apackaged viral vector. In general, packaged viral vectors include a viral vector packaged in a capsid. Viral vectors and viral capsids are discussed in the ensuing sections. The nucleic acid packaged in the rAAV vector can be single-stranded (ss), self-complementary (sc), or double- stranded (ds). It is expected that the constructs comprising any of SEQ ID NOs: 4-6 or SEQ IDNOs:11-12 are capable of desired packaging and expression. In some embodiments, SEQ ID NOs:5-6 or SEQ ID NOs: 11-12, are capable of desired packaging and expression. Viral Vector Typically, viral vectors carrying transgenes are assembled from polynucleotides encodingthe transgene, suitable regulatory elements, and elements necessary for production of viral proteinswhich mediate cell transduction. Examples of a viral vector include but are not limited to adenoviral, retroviral, lentiviral, herpesvirus and adeno-associated virus (AAV) vectors. The viral vector component of the packaged viral vectors produced according to the methods of the invention includes at least one transgene, e.g., recombinant human FXN gene sequence and associated expression control sequences for controlling expression of the recombinant human FXN gene sequence. In a preferred embodiment, the viral vector includes a portion of a parvovirus genome, such as an AAV genome with rep and cap deleted and / or replaced by the recombinant human FXN andits associated expression control sequences. The recombinant human FXN gene sequence istypically inserted adjacent to one or two (i.e., is flanked by) AAV TRs or TR elements adequate for viral replication (Xiao et al., 1997, J. Virol. 71(2): 941-948), in place of the nucleic acid encoding viral rep and cap proteins. Other regulatory sequences suitable for use in facilitating tissue-specific expression of the recombinant human FXN gene sequence in the target cell may also be included. One skilled in the art would appreciate that an AAV vector comprising a transgene and lacking virus proteins needed for viral replication (e.g., cap and rep), cannot replicate since such proteins are necessary for virus replication and packaging. Further, AAV is a Dependovirus in that it cannot replicate in a cell without co-infection of the cell by a helper virus. Helper viruses include, typically, adenovirus or herpes simplex virus. Alternatively, as discussed below, the helper functions (E1a, E1b, E2a, E4, and VA RNA) can be provided to a packaging cell including by transfecting the cell with one or more nucleic acids encoding the various helper elements and / or the cell can comprise the nucleic acid encoding the helper protein. For instance, HEK 293 were generated by transforming human cells with adenovirus 5 DNA and now express a number of adenoviral genes, including, but not limited to E1 and E3 (see, e.g., Graham et al., 1977, J. Gen.Virol. 36:59-72). Thus, those helper functions can be provided by the HEK 293 packaging cellwithout the need of supplying them to the cell by, e.g., a plasmid encoding them. The viral vector may be any suitable nucleic acid construct, such as a DNA or RNA construct and may be single stranded, double stranded, or duplexed (i.e., self-complementary as described in WO 2001 / 92551). One skilled in the art would appreciate that an rAAV vector can further include a “stuffer” or “filler” sequence (filler / stuffer) where the nucleic acid comprising the transgene is less than theapproximately 4.1 to 4.9 kb size for optimal packaging of the nucleic acid into the AAV capsid.See, Grieger and Samulski, 2005, J. Virol. 79(15):9933-9944. That is, AAV vectors typically accept inserts of DNA having a defined size range which is generally about 4 kb to about 5.2 kb, or slightly more. Thus, for shorter sequences, inclusion of a filler / stuffer in the insert fragment in order to adjust the length to near or at the normal size of the virus genomic sequence acceptable for AAV vector packaging into a virus particle. In various embodiments, a filler / stuffer nucleic acid sequence is an untranslated (non-protein encoding) segment of nucleic acid. In particular embodiments of an rAAV vector, a heterologous polynucleotide sequence has a length less than 4.7 kb and the filler / stuffer polynucleotide sequence has a length that when combined (e.g., inserted into a vector) with the heterologous polynucleotide sequence has a total length between about 3.0-5.5 kb, or between about 4.0-5.0 kb, or between about 4.3-4.8 kb. An intron can also function as a filler / stuffer polynucleotide sequence in order to achieve a length for AAV vector packaging into a virus particle. Introns and intron fragments that function as a filler / stuffer polynucleotide sequence also can enhance expression. For example, inclusion of an intron element may enhance expression compared with expression in the absence of the intron element (Kurachi et al., 1995, J. Biol. Chem. 270(10):5276-5281). Furthermore, filler / stuffer polynucleotide sequences are well known in the art and include, but are not limited to, those described in WO 2014 / 144486. Viral Capsid The viral capsid component of the packaged viral vectors may be a parvovirus capsid. AAV Cap and chimeric capsids are preferred. Examples of suitable parvovirus viral capsid components are capsid components from the family Parvoviridae, such as an autonomous parvovirus or a Dependovirus. For example, the viral capsid may be an AAV capsid (e.g., AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7 AAV8, AAV9, AAV10, AAV11, AAV12, AAV1.1, AAV2.5, AAV6.1, AAV6.3.1, AAV9.45, AAVrh10, AAVrh74, RHM4-1 (SEQ ID NO:5 of WO 2015 / 013313), AAV2-TT, AAV2-TT-S312N, AAV3B-S312N, AAV-LK03, AAVrh10, AAV- PHP.B, AAV-PHP.eB, AAV-PHP.S, AAV2.GL, AAV2.NN, snake AAV, avian AAV, bovine AAV, canine AAV, equine AAV, ovine AAV, goat AAV, shrimp AAV, and any other AAV now known or later discovered. see, e.g., Fields et al., VIROLOGY, volume 2, chapter 69 (4thed., Lippincott-Raven Publishers). Capsids may be derived from a number of AAV serotypes disclosed in U.S. Pat. No.7,906,111; Gao et al., 2004, J. Virol. 78:6381; Moris et al., 2004, Virol. 33:375;WO 2013 / 063379; WO 2014 / 194132; and include true type AAV (AAV-TT) variants disclosed inWO 2015 / 121501, and RHM4-1, RHM15-1 through RHM15-6, and variants thereof, disclosed in WO 2015 / 013313, and one skilled in the art would know there are likely other variants not yet identified that perform the same or similar function, or may include components from two or more AAV capsids. A full complement of AAV Cap proteins includes VP1, VP2, and VP3. The ORF comprising nucleotide sequences encoding AAV VP capsid proteins may comprise less than a full complement AAV Cap protein or the full complement of AAV Cap proteins may be provided. One or more of the AAV Cap proteins may be a chimeric protein, including amino acid sequences of AAV Caps from two or more viruses, preferably two or more AAVs, as described in Rabinowitz et al., U.S. Pat. No.6,491,907, the entire disclosure of which is incorporated herein by reference. For example, the chimeric virus capsid can include an AAV1 Cap protein or subunit and at least one AAV2 Cap or subunit. The chimeric capsid can, for example, include an AAVcapsid with one or more B19 Cap subunits, e.g., an AAV Cap protein or subunit can be replacedby a B19 Cap protein or subunit. For example, in a preferred embodiment, the Vp3 subunit of the AAV capsid can be replaced by the Vp2 subunit of B19. Another embodiment includes chimeric viral strains synthesized include the combination of AAV backbones from AAV2, AAV3, AAV6, AAV8, etc., with a galactose (Gal) bindingfootprint from AAV9. Adeno-associated viruses (AAVs) are helper-dependent parvoviruses thatexploit heparan sulfate (HS), galactose (Gal), or sialic acids (Sia) as primary receptors for cell surface binding. For instance, AAV serotypes 2 and 3b utilize HS. AAV1, 4, and 5 bind Sia with different linkage specificities, AAV serotype 6, which recognizes both Sia and HS, whereas AAV9 exploits Gal for host cell attachment. Specifically, the galactose (Gal) binding footprint from AAV9 was grafted onto the heparin sulfate-binding AAV serotype 2 and just grafting of orthogonal glycan binding footprints improves transduction efficiency. A new dual glycan-binding strain (AAV2G9) and a chimeric, muscle-tropic strain (AAV2i8G9) were generated by incorporating the Gal binding footprint from AAV9 into the AAV2 VP3 backbone or the chimeric AAV2i8 capsid template using structural alignment and site-directed mutagenesis. In vitro binding and transduction assays confirmed the exploitation of both HS and Gal receptors by AAV2G9 forcell entry. Subsequent in vivo characterization of the kinetics of transgene expression and vectorgenome biodistribution profiles indicate fast, sustained, and enhanced transgene expression by thisrationally engineered chimeric AAV strain. A similar, improved transduction profile was observedwith the liver-detargeted, muscle-specific AAV2i8G9 chimera (Shen, et al., 2013, J. Biol. Chem. 288(4):28814-28823). Such new grafting combination is fully described in WO2014 / 144229 the contents of which are incorporated by reference herein. Additional liver de-targeted AAVs, such as AAV9.45, are described in Pulicherla et al., 2011, Molecular Therapy 19(6):1070-1078, the contents of which are incorporated by reference as if set forth in their entirety herein. In yet another embodiment the present invention provides for the use of ancestral AAVvectors for use in therapeutic in vivo gene therapy. Specifically, in silico-derived sequences weresynthesized de novo and characterized for biological activities. This effort led to the generation of nine functional putative ancestral AAVs and the identification of Anc80, the predicted ancestor of AAV serotypes 1, 2, 8 and 9 (Zinn et al., 2015, Cell Reports 12:1056-1068). Predicting and synthesis of such ancestral sequences in addition to assembling into a virus particle may be accomplished by using the methods described in WO 2015 / 054653, the contents of which are incorporated by reference herein. Notably, the use of the virus particles assembled from ancestral viral sequences exhibit reduced susceptibility to pre-existing immunity in current day human population than do contemporary viruses or portions thereof. Production of Packaged Viral Vector The invention includes packaging cells, which are encompassed by “host cells,” which may be cultured to produce packaged viral vectors of the invention. The packaging cells of the invention generally include cells with heterologous (1) viral vector function(s), (2) packaging function(s), and (3) helper function(s). Each of these component functions is discussed in the ensuing sections. Initially, the vectors can be made by several methods known to skilled artisans (see, e.g., WO 2013 / 063379). A preferred method is described in Grieger, et al. 2015, Molecular Therapy 24(2):287-297, the contents of which are incorporated by reference herein for all purposes. Oneoption is to utilize efficient transfection of HEK293 cells is used as a starting point, wherein anadherent HEK293 cell line from a qualified clinical master cell bank is used to grow in animal component-free suspension conditions in shaker flasks and WAVE bioreactors that allow for rapid and scalable rAAV production. Using the triple transfection method (e.g., WO 96 / 40240), the suspension HEK293 cell line generates greater than 1×105vector genome containing particles (vg) / cell or greater than 1×1014vg / L of cell culture when harvested 48 hours post-transfection. More specifically, triple transfection refers to the fact that the packaging cell is transfected with three plasmids: one plasmid encodes the AAV rep and cap genes, another plasmid encodes various helper functions (e.g., adenovirus or HSV proteins such as E1a, E1b, E2a, E4, and VA RNA, and another plasmid encodes the transgene and its various control elements (e.g., recombinant FXNgene and non-native or endogenous promoter, e.g. SEQ ID NOs:4-6 or SEQ ID NOs:11-12 ).Another option is to utilize a baculoviral production system as described in WO / 2008 / 024998. To achieve the desired yields, several variables are optimized such as selection of a compatible serum-free suspension media that supports both growth and transfection, selection of a transfection reagent, transfection conditions and cell density. A universal purification strategy, based on ion exchange chromatography methods, was also developed that resulted in high purity vector preps of AAV serotypes 1-6, 8, 9 and various chimeric capsids. This user-friendly process can be completed within one week, results in high full to empty particle ratios (>90% full particles), provides post-purification yields (>1×1013vg / L) and purity suitable for clinical applications and is universal with respect to all serotypes and chimeric particles. This scalable manufacturing technology has been utilized to manufacture GMP Phase I clinical AAV vectors for retinal neovascularization (AAV2), Hemophilia B (scAAV8), Giant Axonal Neuropathy (scAAV9) and Retinitis Pigmentosa (AAV2), which have been administered into patients. In addition, a minimumof a 5-fold increase in overall vector production by implementing a perfusion method that entailsharvesting rAAV from the culture media at numerous time-points post-transfection. Viral Vector Functions The packaging cells typically include viral vector functions, along with packaging and vector functions. The viral vector functions typically include a portion of a parvovirus genome, such as an AAV genome, with rep and cap deleted and replaced by the recombinant human FXN sequence and its associated expression control sequences. The viral vector functions include sufficient expression control sequences to result in replication of the viral vector for packaging. Typically, the viral vector includes a portion of a parvovirus genome, such as an AAV genome with rep and cap deleted and replaced by the transgene and its associated expression control sequences. The transgene is typically flanked by two AAV ITRs, in place of the deleted viral repand cap ORFs. Appropriate expression control sequences are included, such as a tissue-specificpromoter and other regulatory sequences suitable for use in facilitating tissue-specific expression of the transgene in the target cell. The transgene is typically a nucleic acid sequence that can be expressed to produce a therapeutic polypeptide or a marker polypeptide. “Duplexed vectors” may interchangeably be referred to herein as “dimeric” or “self- complementary” vectors. The duplexed parvovirus particles may, for example, comprise aparvovirus capsid containing virion DNA (vDNA). The vDNA is self-complementary so that itmay form a hairpin structure upon release from the viral capsid. The duplexed vDNA appears to provide to the host cell a double-stranded DNA that may be expressed (i.e., transcribed and, optionally, translated) by the host cell without the need for second-strand synthesis, as required with conventional parvovirus vectors. Duplexed / self-complementary rAAV vectors are well- known in the art and described, e.g., in WO 2001 / 92551, WO 2015 / 006743, and many others. The viral vector functions may suitably be provided as duplexed vector templates, as described in U.S. Pat. No. 7,465,583 to Samulski et al. (the entire disclosure of which is incorporated herein by reference for its teaching regarding duplexed vectors). Duplexed vectors are dimeric self-complementary (sc) polynucleotides (typically, DNA). For example, the DNA of the duplexed vectors can be selected so as to form a double-stranded hairpin structure due to intrastrand base pairing. Both strands of the duplexed DNA vectors may be packaged within a viral capsid. The duplexed vector provides a function comparable to double-stranded DNA virus vectors and can alleviate the need of the target cell to synthesize complementary DNA to the single-stranded genome normally encapsulated by the virus. The duplexed vector genome preferablycontains sufficient packaging sequences for encapsidation within the selected parvovirus capsid (e.g., AAV capsid). Those skilled in the art will appreciate that the duplexed vDNA may not existin a double-stranded form under all conditions but has the ability to do so under conditions thatfavor annealing of complementary nucleotide bases. “Duplexed parvovirus particle” encompasses hybrid, chimeric and targeted virus particles. Preferably, the duplexed parvovirus particle has an AAV capsid, which may further be a chimeric or targeted capsid, as described above. The ITR(s) (resolvable and non-resolvable) or TRs selected for use in the viral vectors are preferably AAV sequences, with serotypes 1, 2, 3, 4, 5 and 6 being preferred. Resolvable AAVITRs need not have a wild-type ITR sequence (e.g., a wild-type sequence may be altered byinsertion, deletion, truncation or missense mutations), as long as the ITR mediates the desired functions, e.g., virus packaging, integration, and / or provirus rescue, and the like. The ITRs may be synthetic sequences that function as AAV inverted terminal repeats, such as the “double-D sequence” as described in U.S. Pat. No.5,478,745 to Samulski et al., the entire disclosure of which is incorporated in its entirety herein by reference. Typically, but not necessarily, the ITRs are from the same parvovirus, e.g., both ITR sequences are from AAV2. The packaging functions include capsid components. The capsid components are preferably from a parvoviral capsid, such as an AAV capsid or a chimeric AAV capsid function. Examples of suitable parvovirus viral capsid components are capsid components from the family Parvoviridae, such as an autonomous parvovirus or a Dependovirus. For example, the capsid components may be selected from AAV capsids, e.g., AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, AAVrh10, AAVrh74, RHM4-1, RHM15-1, RHM15-2, RHM15-3 / RHM15-5, RHM15-4, RHM15-6, AAV Hu.26, AAV1.1, AAV2.5, AAV6.1, AAV6.3.1, AAV9.45, AAV2i8, AAV2G9, AAV2i8G9, AAV2-TT AAV2-TT- S312N), AAV3B-S312N, and AAV-LK03 (See, US Patent No. 10,548,947, and other novelcapsids as yet unidentified or from non-human primate sources. Capsid components may includecomponents from two or more AAV capsids. In another embodiment, one or more of the VP capsid proteins is a chimeric protein, comprising amino acid sequences from two or more viruses, preferably two or more AAVs, as described in Rabinowitz et al., U.S. Pat. No. 6,491,907. A chimeric capsid is described herein as having at least one amino acid residue from one serotype combined with another serotype that is sufficient to modify a) viral yield, b) immune response, c) targeting, d) de-targeting, etc. Further chimeric proteins can be made by instruction set forth in Li, et al., 2008, Mol. Ther. 16(7):1252-1260, the contents of which are incorporated by reference herein. Specifically, a DNA shuffling-based approach was used for developing cell type-specific vectors through directed evolution. Capsid genomes of adeno-associated virus (AAV) serotypes 1-9 were randomly fragmented and reassembled using PCR to generate a chimeric capsid library. A single infectious clone (chimeric-1829) containing genome fragments from AAV1, 2, 8, and 9 was isolated from an integrin minus hamster melanoma cell line previously shown to have low permissiveness to AAV. Molecular modeling studies suggest that AAV2 contributes to surface loops at the icosahedralthreefold axis of symmetry, while AAV1 and 9 contribute to two- and five-fold symmetryinteractions, respectively. The C-terminal domain (AAV9) was identified as a critical structural determinant of melanoma tropism through rational mutagenesis. Chimeric-1829 utilizes heparan sulfate as a primary receptor and transduces melanoma cells more efficiently than all serotypes. Application of this technology to alternative cell / tissue types using AAV or other viral capsid sequences is likely to yield a new class of biological nanoparticles as vectors for human gene transfer. The packaged viral vector generally includes the recombinant human FXN sequence andexpression control sequences flanked by TR elements, referred to herein as the “transgene” or “transgene expression cassette,” sufficient to result in packaging of the vector DNA andsubsequent expression of the modified FXN sequence in the transduced cell. The viral vectorfunctions may, for example, be supplied to the cell as a component of a plasmid or an amplicon. The viral vector functions may exist extra chromosomally within the cell line and / or may be integrated into the cell's chromosomal DNA. Any method of introducing the nucleotide sequence carrying the viral vector functions into a cellular host for replication and packaging may be employed, including but not limited to, electroporation, calcium phosphate precipitation, microinjection, cationic or anionic liposomes, and liposomes in combination with a nuclear localization signal. In embodiments wherein the viral vector functions are provided by transfection using a virus vector; standard methods for producing viral infection may be used. Packaging Functions The packaging functions include genes for viral vector replication and packaging. Thus, for example, the packaging functions may include, as needed, functions necessary for viral gene expression, viral vector replication, rescue of the viral vector from the integrated state, viral gene expression, and packaging of the viral vector into a viral particle. The packaging functions may be supplied together or separately to the packaging cell using a genetic construct such as a plasmid or an amplicon, a Baculovirus, or HSV helper construct. The packaging functions may exist extrachromosomally within the packaging cell but are preferably integrated into the cell's chromosomal DNA. Examples include genes encoding AAV Rep and Cap proteins. rAAV Production Systems Numerous cell culture-based systems are known in the art for production of rAAV particles, any of which can be used to practice a method disclosed herein. The cell culture-based systems include transfection, stable cell line production, and infectious hybrid virus production systems which include Adenovirus-AAV hybrids, herpesvirus-AAV hybrids and baculovirus- AAV hybrids. rAAV production cultures for the production of rAAV virus particles all require; (1) suitable host cells, including, for example, human-derived cell lines such as HeLa, A549, or HEK293 cells and their derivatives (HEK293T cells, HEK293F cells), mammalian cell lines suchas Vero, CHO cells or CHO-derived cells, or insect- derived cell lines such as SF-9 in the case ofbaculovirus production systems; (2) suitable helper virus function, provided by wild type or mutant adenovirus (such as temperature sensitive adenovirus), herpes virus, baculovirus, or a plasmid construct providing helper functions; (3) AAV rep and cap genes and gene products; (4) a transgene (such as a therapeutic transgene) flanked by AAV ITR sequences; and (5) suitable media and media components to support rAAV production. A skilled artisan is aware of the numerous methods by which AAV rep and cap genes, AAV helper genes (e.g., adenovirus Ela gene, Elb gene, E4 gene, E2a gene, and VA gene), and rAAV genomes (comprising one or more genes of interest flanked by inverted terminal repeats (ITRs)) can be introduced into cells to produce or package rAAV. The phrase “adenovirus helper functions” refers to a number of viral helper genes expressed in a cell (as RNA or protein) such that the AAV grows efficiently in the cell. The skilled artisan understands that helper viruses, including adenovirus and herpes simplex virus (HSV), promote AAV replication and certain genes have been identified that provide the essential functions, e.g. the helper may induce changes to the cellular environment that facilitate such AAV gene expression and replication. In some embodiments, AAV rep and cap genes, helper genes, and rAAV genomes are introduced into cells by transfection of one or more plasmid vectors encoding the AAV rep and cap genes, helper genes, and rAAV genome. In some embodiments, AAV rep and cap genes, helper genes, and rAAV genomes can be introduced into cells by transduction with viral vectors, for example, rHSV vectorsencoding the AAV rep and cap genes, helper genes, and rAAV genome. In some embodiments,one or more of AAV rep and cap genes, helper genes, and rAAV genomes are introduced into the cells by transduction with an rHSV vector. In some embodiments, the rHSV vector encodes the AAV rep and cap genes. In some embodiments, the rHSV vector encodes the helper genes. In some embodiments, the rHSV vector encodes the rAAV genome. In some embodiments, the rHSVvector encodes the AAV rep and cap genes. In some embodiments, the rHSV vector encodes thehelper genes and the rAAV genome. In some embodiments, the rHSV vector encodes the helper genes and the AAV rep and cap genes. Any suitable media known in the art may be used for the production of rAAV particles. These media include, without limitation, media produced by Hyclone Laboratories and JRH including Modified Eagle Medium (MEM), Dulbecco's Modified Eagle Medium (DMEM), and Sf-900 II SFM media as described in U.S. Pat. No. 6,723,551, which is incorporated herein byreference in its entirety. In some embodiments, the medium comprises Dynamis™ Medium,FreeStyle™ 293 Expression Medium, or Expi293™ Expression Medium from Invitrogen / ThermoFisher. In some embodiments, the medium comprises Dynamis™ Medium. In someembodiments, a method disclosed herein uses a cell culture comprising a serum-free medium, an animal -component free medium, or a chemically defined medium. In some embodiments, the medium is an animal-component free medium. In some embodiments, the medium comprises serum. In some embodiments, the medium comprises fetal bovine serum. In some embodiments, the medium is a glutamine-free medium. In some embodiments, the medium comprises glutamine. In some embodiments, the medium is supplemented with one or more of nutrients, salts, buffering agents, and additives (e.g., antifoam agent). In some embodiments, the medium is supplemented with glutamine. In some embodiments, the medium is supplemented with serum. In some embodiments, the medium is supplemented with fetal bovine serum. In some embodiments, the medium is supplemented with poloxamer, e.g., Kolliphor® P 188 Bio. In some embodiments, a medium is a base medium. In some embodiments, the medium is a feed medium. rAAV production cultures can routinely be grown under a variety of conditions (over a wide temperature range, for varying lengths of time, and the like) suitable to the particular host cell being utilized. As is known in the art, rAAV production cultures include attachment-dependent cultures which can be cultured in suitable attachment-dependent vessels such as, for example, roller bottles, hollow fiber filters, multilayer or multitray tissue culture flasks (or stacks, e.g. hyperstacks), microcarriers, and packed-bed or fluidized-bed bioreactors. rAAV vector productioncultures may also include suspension- adapted host cells such as HeLa cells, HEK293 cells, HEK293 derived cells (e.g., HEK293T cells, HEK293F cells), Vero cells, CHO cells, CHO-K1 cells, CHO derived cells, EB66 cells, BSC cells, HepG2 cells, LLC-MK cells, CV-l cells, COS cells, MDBK cells, MDCK cells, CRFK cells, RAF cells, RK cells, TCMK-l cells, LLCPK cells, PK15 cells, LLC-RK cells, MDOK cells, BHK cells, BHK-21 cells, NS-l cells, MRC-5 cells, WI- 38 cells, BHK cells, 3T3 cells, 293 cells, RK cells, Per.C6 cells, chicken embryo cells and SF-9 cells which can be cultured in a variety of ways including, for example, spinner flasks, stirred tank bioreactors, and disposable systems such as the Wave bag system. Numerous suspension cultures are known in the art for production of rAAV particles, including for example, the cultures disclosed in U.S. Patent Nos. 6,995,006, 9,783,826, and in U.S. Pat. Appl. Pub. No. 20120122155, each of which is incorporated herein by reference in its entirety. Packaging Cell Any cell or cell line that is known in the art to produce rAAV particles can be used in any one of the methods disclosed herein. In some embodiments, a method of producing rAAV particles or increasing the production of rAAV particles disclosed herein uses HeLa cells, HEK293 cells, HEK293 derived cells (e.g., HEK293T cells, HEK293F cells), Vero cells, CHO cells, CHO-K1 cells, CHO derived cells, EB66 cells, BSC cells, HepG2 cells, LLC-MK cells, CV-l cells, COS cells, MDBK cells, MDCK cells, CRFK cells, RAF cells, RK cells, TCMK-l cells, LLCPK cells, PK15 cells, LLC-RK cells, MDOK cells, BHK cells, BHK-21 cells, NS-l cells, MRC-5 cells, WI- 38 cells, BHK cells, 3T3 cells, 293 cells, RK cells, Per.C6 cells, chicken embryo cells or SF-9cells. In some embodiments, a method disclosed herein uses mammalian cells. In someembodiments, a method disclosed herein uses insect cells, e.g., SF-9 cells. In some embodiments, a method disclosed herein uses HEK293 cells. In some embodiments, a method disclosed herein uses HEK293 cells adapted for growth in suspension culture. In some embodiments, a cell culture disclosed herein is a suspension culture. In some embodiments, a cell culture disclosed herein is a suspension culture comprising HEK293. In some embodiments, a cell culture disclosed herein is a suspension culture comprising HEK293 cells adapted for growth in suspension culture. In some embodiments, a cell culture disclosed herein comprises a serum-free medium, an animal-component free medium, or a chemically defined medium. In some embodiments, a cell culture disclosed herein comprises a serum -free medium. In some embodiments, suspension-adapted cells are cultured in a shaker flask, a spinner flask, a cellbag, or a bioreactor. In some embodiments, a cell culture disclosed herein comprises cells attached to a substrate (e.g., microcarriers) that are themselves in suspension in a medium. In some embodiments, the cells are HEK293 cells. In some embodiments, a cell culture disclosed herein is an adherent culture. In some embodiments, a cell culture disclosed herein is an adherent culture comprising HEK293. In some embodiments, a cell culture disclosed herein comprises a serum-free medium, an animal- component free medium, or a chemically defined medium. In some embodiments, a cell culture disclosed herein comprises a serum-free medium. In some embodiments, a cell culture disclosed herein comprises a high-density cell culture. In some embodiments, the culture has a total cell density of between about lxl0E+06 cells / ml and about 30xl0E+06 cells / ml. In some embodiments, more than about 50% of the cells are viable cells. In some embodiments, the cells are HeLa cells, HEK293 cells, HEK293 derived cells (e.g., HEK293T cells, HEK293F cells), Vero cells, or SF-9 cells. In further embodiments, the cells are HEK293 cells. In further embodiments, the cells are HEK293 cells adapted for growth in suspension culture. Cell lines for use as packaging cells include insect cell lines. Any insect cell which allows for replication of AAV and which can be maintained in culture can be used in accordance with thepresent invention. Examples include Spodoptera frugiperda, such as the Sf9 or Sf21 celllines, Drosophila spp. cell lines, or mosquito cell lines, e.g., Aedes albopictus derived cell lines.A preferred cell line is the Spodoptera frugiperda Sf9 cell line. The following references areincorporated herein for their teachings concerning use of insect cells for expression of heterologous polypeptides, methods of introducing nucleic acids into such cells, and methods of maintaining such cells in culture: Methods in Molecular Biology, ed. Richard, Humana Press, N J (1995); O'Reilly et al., Baculovirus Expression Vectors: A Laboratory Manual, Oxford Univ. Press (1994); Samulski et al., 1989, J. Virol. 63:3822-3828; Kajigaya et al., 1991, Proc. Nat'l. Acad. Sci. USA 88: 4646-4650; Ruffing et al., 1992, J. Virol.66:6922-6930; Kimbauer et al., 1996, Virol.219:37- 44; Zhao et al., 2000, Virol.272:382-393; and Samulski et al., U.S. Pat. No.6,204,059. For example, virus capsids utilized in embodiments described herein can be produced using any method known in the art, e.g., by expression from a baculovirus (Brown et al., (1994) Virology 198:477-488). As a further alternative, the virus vectors of the invention can be produced in insect cells using baculovirus vectors to deliver the rep / cap genes and rAAV template as described, for example, by Urabe et al., 2002, Human Gene Therapy 13:1935-1943. In another aspect, provided herein are methods of rAAV production in insect cells wherein a baculovirus packaging system or vectors may be constructed to carry the AAV Rep and Cap coding region by engineering these genes into the polyhedrin coding region of a baculovirus vector and producing viral recombinants by transfection into a host cell. Notably when using Baculovirus production for AAV, preferably the AAV DNA vector product is a self-complementary AAV like molecule without using mutation to the AAV ITR. This appears to be a by-product of inefficient AAV rep nicking in insect cells which results in a self-complementary DNA molecule by virtue of lack of functional Rep enzyme activity. The host cell is a baculovirus-infected cell or has introduced therein additional nucleic acid encoding baculovirus helper functions or includes these baculovirus helper functions therein. These baculovirus viruses can express the AAV components and subsequently facilitate the production of the capsids. During production, the packaging cells generally include one or more viral vector functions along with helper functions and packaging functions sufficient to result in replication and packaging of the viral vector. These various functions may be supplied together or separately to the packaging cell using a genetic construct such as a plasmid or an amplicon, and they may exist extrachromosomally within the cell line or integrated into the cell's chromosomes. The cells may be supplied with any one or more of the stated functions already incorporated, e.g., a cell line with one or more vector functions incorporated extrachromosomally or integrated into the cell's chromosomal DNA, a cell line with one or more packaging functions incorporated extrachromosomally or integrated into the cell's chromosomal DNA, or a cell line with helper functions incorporated extrachromosomally or integrated into the cell's chromosomal DNA. rAAV Purification The rAAV particles produced can be isolated using methods known in the art. In someembodiments, methods of isolating rAAV particles comprises downstream processing such as, for example, harvest of a cell culture, clarification of the harvested cell culture (e.g., by centrifugation or depth filtration), tangential flow filtration, affinity chromatography, anion exchange chromatography, cation exchange chromatography, size exclusion chromatography, hydrophobic interaction chromatography, hydroxylapatite chromatography, sterile filtration, or any combination(s) thereof. In some embodiments, downstream processing includes at least 2, at least 3, at least 4, at least 5 or at least 6 of: harvest of a cell culture, clarification of the harvested cell culture (e.g., by centrifugation or depth filtration), tangential flow filtration, affinity chromatography, anion exchange chromatography, cation exchange chromatography, size exclusion chromatography, hydrophobic interaction chromatography, hydroxylapatite chromatography, and sterile filtration. In some embodiments, downstream processing comprises harvest of a cell culture, clarification of the harvested cell culture (e.g., by depth filtration), sterile filtration, tangential flow filtration, affinity chromatography, and anion exchange chromatography. In some embodiments, downstream processing comprises clarification of a harvested cell culture, sterile filtration, tangential flow filtration, affinity chromatography, and anion exchange chromatography. In some embodiments, downstream processing comprises clarification of a harvested cell culture by depth filtration, sterile filtration, tangential flow filtration, affinity chromatography, and anion exchange chromatography. In some embodiments, clarification of the harvested cell culture comprises sterile filtration. In some embodiments, downstream processing does not include centrifugation. In some embodiments, a method of isolating rAAV particles comprises harvest of a cell culture, clarification of the harvested cell culture (e.g., by depth filtration), a first sterile filtration,a first tangential flow filtration, affinity chromatography, anion exchange chromatography (e.g.,monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), a second tangential flow filtration, and a second sterile filtration. In some embodiments, a method of isolating rAAV particles disclosed herein comprises harvest of a cell culture, clarification of the harvested cell culture (e.g., by depth filtration), a first sterile filtration, affinity chromatography, anion exchange chromatography (e.g., monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), a tangential flow filtration, and a second sterile filtration. In some embodiments, a method of isolating rAAV particles comprises clarification of a harvested cell culture, a first sterile filtration, a first tangential flow filtration, affinity chromatography, anion exchange chromatography (e.g., monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), a second tangential flow filtration, and a second sterile filtration. In some embodiments, a method of isolating rAAV particles disclosed herein comprises clarification of a harvested cell culture, a first sterile filtration, affinity chromatography, anion exchange chromatography (e.g., monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), tangential flow filtration, and a second sterile filtration. In some embodiments, a method of isolating rAAV particles comprises clarification of a harvested cell culture by depth filtration, a first sterile filtration, a first tangential flow filtration, affinity chromatography, anion exchange chromatography (e.g., monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), a second tangential flow filtration, and a second sterile filtration. In some embodiments, a method of isolating rAAV particles disclosed herein comprises clarification of a harvested cell culture by depth filtration, a first sterile filtration, affinity chromatography, anion exchange chromatography (e.g., monolith anion exchange chromatography or AEX chromatography using a quaternary amine ligand), tangential flow filtration, and a second sterile filtration. In some embodiments, the method does not include centrifugation. In someembodiments, clarification of the harvested cell culture comprises sterile filtration.Recombinant AAV particles can be harvested from rAAV production cultures by harvest of the production culture comprising host cells or by harvest of the spent media from the production culture, provided the cells are cultured under conditions known in the art to cause release of rAAV particles into the media from intact host cells. Recombinant AAV particles can also be harvested from rAAV production cultures by lysis of the host cells of the production culture. Suitable methods of lysing cells are also known in the art and include for example multiple freeze / thaw cycles, sonication, microfluidization, and treatment with chemicals, such as detergents and / or proteases. At harvest, rAAV production cultures can contain one or more of the following: (1) host cell proteins; (2) host cell DNA; (3) plasmid DNA; (4) helper virus; (5) helper virus proteins; (6) helper virus DNA; and (7) media components including, for example, serum proteins, amino acids, transferrins and other low molecular weight proteins. rAAV production cultures can further contain product-related impurities, for example, inactive vector forms, empty viral capsids, aggregated viral particles or capsids, mis-folded viral capsids, degraded viral particle. In some embodiments, the rAAV production culture harvest is clarified to remove host cell debris. In some embodiments, the production culture harvest is clarified by filtration through a series of depth filters. Clarification can also be achieved by a variety of other standard techniques known in the art, such as, centrifugation or filtration through any cellulose acetate filter of 0.2 mm or greater pore size known in the art. In some embodiments, clarification of the harvested cell culture comprises sterile filtration. In some embodiments, the production culture harvest is clarified by centrifugation. In some embodiments, clarification of the production culture harvestdoes not include centrifugation.In some embodiments, harvested cell culture is clarified using filtration. In some embodiments, clarification of the harvested cell culture comprises depth filtration. In someembodiments, clarification of the harvested cell culture further comprises depth filtration andsterile filtration. In some embodiments, harvested cell culture is clarified using a filter train comprising one or more different filtration media. In some embodiments, the filter train comprises a depth filtration media. In some embodiments, the filter train comprises one or more depth filtration media. In some embodiments, the filter train comprises two depth filtration media. In some embodiments, the filter train comprises a sterile filtration media. In some embodiments, thefilter train comprises 2 depth filtration media and a sterile filtration media. In some embodiments,the depth filter media is a porous depth filter. In some embodiments, the filter train comprises Clarisolve® 20MS, Millistak+® C0HC, and a sterilizing grade filter media. In some embodiments, the filter train comprises Clarisolve® 20MS, Millistak+® C0HC, and Sartopore® 2 XLG 0.2 pm. In some embodiments, the harvested cell culture is pretreated before contacting it with the depth filter. In some embodiments, the pretreating comprises adding a salt to the harvested cell culture.In some embodiments, the pretreating comprises adding a chemical flocculant to the harvested cellculture. In some embodiments, the harvested cell culture is not pre-treated before contacting it with the depth filter. In some embodiments, the clarified feed is concentrated via tangential flow filtration ("TFF") before being applied to a chromatographic medium, for example, affinity chromatographymedium. Large scale concentration of viruses using TFF ultrafiltration has been described by Paul et al, Human Gene Therapy 4:609-615 (1993). TFF concentration of the clarified feed enables a technically manageable volume of clarified feed to be subjected to chromatography and allows for more reasonable sizing of columns without the need for lengthy recirculation times. In some embodiments, the clarified feed is concentrated between at least two-fold and at least ten-fold. In some embodiments, the clarified feed is concentrated between at least ten-fold and at least twenty-fold. In some embodiments, the clarified feed is concentrated between at least twenty-fold and atleast fifty-fold. In some embodiments, the clarified feed is concentrated about twenty-fold. One of ordinary skill in the art will also recognize that TFF can also be used to remove small molecule impurities (e.g., cell culture contaminants comprising media components, serum albumin, or other serum proteins) form the clarified feed via diafiltration. In some embodiments, the clarified feed is subjected to diafiltration to remove small molecule impurities. In some embodiments, the diafiltration comprises the use of between about 3 and about 10 diafiltration volume of the buffer. In some embodiments, the diafiltration comprises the use of about 5 diafiltration volume of buffer. One of ordinary skill in the art will also recognize that TFF can also be used at any step in the purification process where it is desirable to exchange buffers before performing the next step in the purification process. In some embodiments, the methods for isolating rAAV from the clarified feed disclosed herein comprise the use of TFF to exchange buffers. Affinity chromatography can be used to isolate rAAV particles from a composition. In some embodiments, affinity chromatography is used to isolate rAAV particles from the clarified feed. In some embodiments, affinity chromatography is used to isolate rAAV particles from the clarified feed that has been subjected to tangential flow filtration. Suitable affinity chromatography media are known in the art and include without limitation, AVB Sepharose™, POROS™CaptureSelect™ AAVX affinity resin, POROS™ CaptureSelect™ AAV9 affinity resin, andPOROS™ CaptureSelect™ AAV8 affinity resin. In some embodiments, the affinitychromatography media is POROS™ CaptureSelect™ AAV9 affinity resin. In some embodiments,the affinity chromatography media is POROS™ CaptureSelect™ AAV8 affinity resin. In someembodiments, the affinity chromatography media is POROS™ CaptureSelect™ AAVX affinityresin. Anion exchange chromatography can be used to isolate rAAV particles from a composition. In some embodiments, anion exchange chromatography is used after affinity chromatography as a final concentration and polish step. Suitable anion exchange chromatography media are known in the art and include without limitation, Unosphere Q (Biorad, Hercules, Calif.), and N-charged amino or imino resins such as e.g., POROS 50 PI, or any DEAE, TMAE, tertiary or quaternary amine, or PEI-based resins known in the art (U.S. Pat. No. 6,989,264; Brument et al., Mol. Therapy 6(5):678-686 (2002); Gao et al., Hum. Gene Therapy 11:2079-2091 (2000)). In some embodiments, the anion exchange chromatography media comprises a quaternary amine. In some embodiments, the anion exchange media is a monolith anion exchange chromatography resin. In some embodiments, the monolith anion exchange chromatography media comprises glycidylmethacrylate-ethylenedimethacrylate or styrene-divinylbenzene polymers. In some embodiments, the monolith anion exchange chromatography media is selected from the groupconsisting of CIMmultus™ QA-l Advanced Composite Column (Quaternary amine),CIMmultus™ DEAE-l Advanced Composite Column (Diethylamino), CIM® QA Disk(Quaternary amine), CIM® DEAE, and CIM® EDA Disk (Ethylene diamino). In someembodiments, the monolith anion exchange chromatography media is CIMmultus™ QA-lAdvanced Composite Column (Quaternary amine). In some embodiments, the monolith anion exchange chromatography media is CIM® QA Disk (Quaternary amine). In some embodiments, the anion exchange chromatography media is CIM QA (BIA Separations, Slovenia). In some embodiments, the anion exchange chromatography media is BIA CIM® QA-80 (Column volume is 80mL). One of ordinary skill in the art can appreciate that wash buffers of suitable ionic strengthcan be identified such that the rAAV remains bound to the resin while impurities, including withoutlimitation impurities which may be introduced by upstream purification steps are stripped away. In additional embodiments the disclosure provides compositions comprising isolated rAAV particles produced according to a method disclosed herein. In some embodiments, the composition is a pharmaceutical composition comprising a pharmaceutically acceptable carrier. As used herein the term "pharmaceutically acceptable" means a biologically acceptableformulation, gaseous, liquid or solid, or mixture thereof, which is suitable for one or more routesof administration, in vivo delivery or contact. A "pharmaceutically acceptable” composition is amaterial that is not biologically or otherwise undesirable, e.g., the material may be administered to a subject without causing substantial undesirable biological effects. Thus, such a pharmaceutical composition may be used, for example in administering rAAV isolated according to the disclosed methods to a subject. Such compositions include solvents (aqueous or non-aqueous), solutions (aqueous or non-aqueous), emulsions (e.g., oil-in-water or water-in-oil), suspensions, syrups, elixirs, dispersion and suspension media, coatings, isotonic and absorption promoting or delaying agents, compatible with pharmaceutical administration or in vivo contact or delivery. Aqueous and non-aqueous solvents, solutions and suspensions may include suspending agents and thickening agents. Such pharmaceutically acceptable carriers include tablets (coated or uncoated), capsules (hard or soft), microbeads, powder, granules and crystals. Supplementary active compounds (e.g., preservatives, antibacterial, antiviral and antifungal agents) can also be incorporated into the compositions. Pharmaceutical compositions can be formulated to be compatible with a particular route of administration or delivery, as set forth herein or known to one of skill in the art. Thus, pharmaceutical compositions include carriers, diluents, or excipients suitable for administration by various routes. Pharmaceutical compositions and delivery systems appropriate for rAAV particles and methods and uses of the invention are known in the art (see, e.g., Remington: The Science and Practice of Pharmacy (2003) 20th ed., Mack Publishing Co., Easton, Pa.; Remington's Pharmaceutical Sciences (1990) 18th ed., Mack Publishing Co., Easton, Pa.; The Merck Index (1996) l2th ed., Merck Publishing Group, Whitehouse, N.J.; Pharmaceutical Principles of Solid Dosage Forms (1993), Technonic Publishing Co., Inc., Lancaster, Pa.; Ansel and Stoklosa, Pharmaceutical Calculations (2001) l lth ed., Lippincott Williams & Wilkins, Baltimore, Md.; and Poznansky et al, Drug Delivery Systems (1980), R. L. Juliano, ed., Oxford, N.Y., pp.253-315). As described herein, the recombinant polynucleotide constructs and rAAVs can be used asa gene therapy to treat FA or related disorders related to a reduction in expression or lack of fullyfunctional frataxin. Additionally, in certain embodiments, constructs and rAAVs as described herein can be used as a gene therapy to increase mitochondrial iron transport and or respiration in a subject in need thereof. Methods of treatment include injecting any of the rAAV’s described herein into a subject in need thereof. One skilled in the art would understand the quantities needed to treat the subject, as it would depend on multiple factors including size, age, and gender of the subject. Methods of Treatment In another aspect, methods of treatment are presented. The methods may comprise administering an effective amount of the pharmaceutical composition comprising any of the desired constructs or rAAV virions described above to a patient in need thereof. As described herein, the FXN polynucleotide construct can be used as a gene therapy totreat Freidreichs’ ataxia (FA) in a subject in need thereof. In some embodiments, a method oftreating FA in a subject is disclosed, wherein the method comprises administering to the subject an effective amount of any of the polynucleotide constructs, vectors, rAAV, or virions described herein. In some embodiments, a method of treating FA in a subject is disclosed, wherein themethod comprises administering to the subject an effective amount of a pharmaceuticalcomposition comprising any of the polynucleotide constructs, vectors, rAAVs, or virionsdescribed herein. The term “subject” is intended to include any mammal. In some embodiments, the subject is cat, a dog, a goat, a non-human primate, a rodent (e.g., a mouse or a rat), a pig, or a sheep. In some embodiments, the subject is a human. In some embodiments, the subject has or is at risk of developing FA. In some embodiments, the subject has previously been identified or diagnosed as having FA. In some embodiments, the subject is at least 5 years old. In some embodiments, the subject is between 5 and 15 years old. In some embodiments, the subject is at least 15 years old. In some embodiments, the subject is at least 25 years old. In some embodiments, the subject is at least 50 years old. In some embodiments, the subject is at least 75 years old. In some embodiments, the subject has symptoms associated with FA. In some embodiments, a symptom associated with FA is selected from awkward and unsteady movements, impaired muscle coordination, difficulty walking, poor balance, impaired sensoryfunctions, loss of normal reflexes, dysarthria, spasticity, scoliosis, difficulty swallowing, hearingloss, vision loss, and fatigue, among others. In some embodiments, a symptom associated with FA is awkward and unsteady movements. In some embodiments, a symptom associated with FA is impaired muscle coordination. In some embodiments, a symptom associated with FA is difficulty walking. In some embodiments, a symptom associated with FA is poor balance. Methods of monitoring motor function and symptoms of FA are known in the art.In some embodiments, a symptom associated with FA is impaired sensory functions. Insome embodiments, a symptom associated with FA is loss of normal reflexes. In some embodiments, a symptom associated with FA is dysarthria. In some embodiments, a symptom associated with FA is spasticity. In some embodiments, a symptom associated with FA is scoliosis. In some embodiments, a symptom associated with FA is difficulty swallowing. In some embodiments, a symptom associated with FA is hearing loss. In some embodiments, a symptom associated with FA is vision loss. In some embodiments, a symptom associated with FA is fatigue. In some embodiments, FA causes a co-occurring disease or disorder. In some embodiments, the co-occurring disease or disorder is heart disease. In some embodiments, the co-occurring disease or disorder is cardiomyopathy. In some embodiments, the co-occurring disease or disorder is diabetes. In some embodiments, the methods may comprise treating a subject in need thereofwherein the treatment comprises administering an FXN polynucleotide construct. In someembodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct, wherein the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NOs: 1 or 3. In some embodiments, the methods may comprise treating asubject in need thereof with an FXN polynucleotide construct, wherein the human FXN codingsequence comprises the nucleotide sequence of SEQ ID NO: 1. In some embodiments, themethods may comprise treating a subject in need thereof with an FXN polynucleotide construct,wherein the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NO: 3. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the human FXN coding sequence comprises at least80% sequence identity to a sequence set forth in SEQ ID NOs: 1 or 3. In some embodiments, themethods may comprise treating a subject in need thereof with an FXN polynucleotide construct,wherein the human FXN coding sequence comprises at least 80% sequence identity to a sequence set forth in SEQ ID NO: 1. In some embodiments, the methods may comprise treating asubject in need thereof with an FXN polynucleotide construct, wherein the human FXN codingsequence comprises at least 85% sequence identity to a sequence set forth in SEQ ID NO: 1. Insome embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct, wherein the human FXN coding sequence comprises at least 90%sequence identity to a sequence set forth in SEQ ID NO: 1. In some embodiments, the methodsmay comprise treating a subject in need thereof with an FXN polynucleotide construct, whereinthe human FXN coding sequence comprises at least 95% sequence identity to a sequence setforth in SEQ ID NO: 1. In some embodiments, the methods may comprise treating a subject inneed thereof with an FXN polynucleotide construct, wherein the human FXN coding sequencecomprises at least 99% sequence identity to a sequence set forth in SEQ ID NO: 1. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the human FXN coding sequence comprises at least80% sequence identity to a sequence set forth in SEQ ID NO: 3. In some embodiments, themethods may comprise treating a subject in need thereof with an FXN polynucleotide construct,wherein the human FXN coding sequence comprises at least 85% sequence identity to a sequence set forth in SEQ ID NO: 3. In some embodiments, the methods may comprise treating asubject in need thereof with an FXN polynucleotide construct, wherein the human FXN codingsequence comprises at least 90% sequence identity to a sequence set forth in SEQ ID NO: 3. Insome embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct, wherein the human FXN coding sequence comprises at least 95%sequence identity to a sequence set forth in SEQ ID NO: 3. In some embodiments, the methodsmay comprise treating a subject in need thereof with an FXN polynucleotide construct, whereinthe human FXN coding sequence comprises at least 99% sequence identity to a sequence set forth in SEQ ID NO: 3. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the promoter fragment comprises the nucleotidesequence of SEQ ID NOs: 7, 13, or 14. In some embodiments, the methods may comprisetreating a subject in need thereof with an FXN polynucleotide construct, wherein the promoterfragment comprises the nucleotide sequence of SEQ ID NO: 7. In some embodiments, themethods may comprise treating a subject in need thereof with an FXN polynucleotide construct,wherein the promoter fragment comprises the nucleotide sequence of SEQ ID NO: 13. In someembodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct, wherein the promoter fragment comprises the nucleotide sequence ofSEQ ID NO: 14.In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the promoter fragment comprises at least 80%, atleast 85%, at least 90%, at least 95%, or at least 99% sequence identity to the nucleotide sequence of SEQ ID NO:7. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the promoter fragment comprises at least 80%, atleast 85%, at least 90%, at least 95%, or at least 99% sequence identity to the nucleotide sequence of SEQ ID NO:13. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the promoter fragment comprises at least 80%, atleast 85%, at least 90%, at least 95%, or at least 99% sequence identity to the nucleotidesequence of SEQ ID NO:14. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct, wherein the 3’ regulatory element comprises woodchuckhepatitis virus post-transcriptional regulatory element (WPRE3) SEQ ID NO: 9. In someembodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct, wherein the 3’ regulatory element comprises a nucleotide sequencewith at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to woodchuckhepatitis virus post-transcriptional regulatory element (WPRE3) SEQ ID NO: 9.In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct wherein the 3’ regulatory element comprises hFXNpA1 (SEQID NO: 16). In some embodiments, the methods may comprise treating a subject in need with anFXN polynucleotide construct wherein the 3’ regulatory element comprises a nucleotidesequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity tohFXNpA1 (SEQ ID NO: 16). In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct comprising the sequence set forth in SEQ ID NOs: 5, 6, 11 or12. In some embodiments, the methods may comprise treating a subject in need thereof with anFXN polynucleotide construct comprising the sequence set forth in SEQ ID NOs: 5, 6, 11 or 12.In some embodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct comprising the sequence set forth in SEQ ID NO: 5. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising the sequence set forth in SEQ ID NO: 6. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising the sequence set forth in SEQ ID NO: 11. In someembodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct comprising the sequence set forth in SEQ ID NO: 12. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct comprising at least 80% sequence identity to SEQ ID NO: 5. Insome embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 85% sequence identity to SEQ ID NO: 5. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 90% sequence identity to SEQ ID NO: 5. In some embodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct comprising at least 95% sequence identity to SEQ ID NO: 5. In someembodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 99% sequence identity to SEQ ID NO: 5. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct comprising at least 80% sequence identity to SEQ ID NO: 6. Insome embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 85% sequence identity to SEQ ID NO: 6. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 90% sequence identity to SEQ ID NO: 6. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 95% sequence identity to SEQ ID NO: 6. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 99% sequence identity to SEQ ID NO: 6. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct comprising at least 80% sequence identity to SEQ ID NO: 11.In some embodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct comprising at least 85% sequence identity to SEQ ID NO: 11. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 90% sequence identity to SEQ ID NO: 11. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 95% sequence identity to SEQ ID NO: 11. In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 99% sequence identity to SEQ ID NO: 11. In some embodiments, the methods may comprise treating a subject in need thereof withan FXN polynucleotide construct comprising at least 80% sequence identity to SEQ ID NO: 12.In some embodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 85% sequence identity to SEQ ID NO: 12. In someembodiments, the methods may comprise treating a subject in need thereof an FXNpolynucleotide construct comprising at least 90% sequence identity to SEQ ID NO: 12. In someembodiments, the methods may comprise treating a subject in need thereof with an FXNpolynucleotide construct comprising at least 95% sequence identity to SEQ ID NO: 12. In someembodiments, the methods may comprise treating a subject in need thereof with an FXN polynucleotide construct comprising at least 99% sequence identity to SEQ ID NO: 12. In some embodiments, the disclosure provides use of an FXN polynucleotide construct inthe manufacture of a medicament for the treatment of FA. In some embodiments, the disclosureprovides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the human FXN coding sequence comprises the nucleotide sequence ofSEQ ID NOs: 1 or 3. In some embodiments, the disclosure provides use of an FXNpolynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NO: 1. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the human FXN coding sequence comprises a nucleotide sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 1. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the human FXN coding sequence comprises the nucleotidesequence of SEQ ID NO: 3. In some embodiments, the disclosure provides use of an FXNpolynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the human FXN coding sequence comprises a nucleotide sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 3. In some embodiments, the disclosure provides use of an FXN polynucleotide construct inthe manufacture of a medicament for the treatment of FA, wherein the promoter fragmentcomprises the nucleotide sequence of SEQ ID NOs: 7, 13 or 14. In some embodiments, thedisclosure provides use of an FXN polynucleotide construct in the manufacture of a medicamentfor the treatment of FA, wherein the promoter fragment comprises the nucleotide sequence ofSEQ ID NO: 7. In some embodiments, the disclosure provides use of an FXN polynucleotideconstruct in the manufacture of a medicament for the treatment of FA, wherein the promoter fragment comprises a nucleotide sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 7. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in themanufacture of a medicament for the treatment of FA, wherein the promoter fragment comprisesthe nucleotide sequence of SEQ ID NO: 13. In some embodiments, the disclosure provides useof an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the promoter fragment comprises a nucleotide sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 13. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in themanufacture of a medicament for the treatment of FA, wherein the promoter fragment comprisesthe nucleotide sequence of SEQ ID NO: 14. In some embodiments, the disclosure provides useof an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the promoter fragment comprises a nucleotide sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 14. In some embodiments, the disclosure provides use of an FXN polynucleotide construct inthe manufacture of a medicament for the treatment of FA, wherein the 3’ regulatory elementcomprises woodchuck hepatitis virus post-transcriptional regulatory element (WPRE3) SEQ IDNO: 9. In some embodiments, the disclosure provides use of an FXN polynucleotide construct inthe manufacture of a medicament for the treatment of FA, wherein the 3’ regulatory element comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence of SEQ ID NO: 9. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA,wherein the 3’ regulatory element comprises hFXNpA1 (SEQ ID NO: 16). In someembodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the 3’ regulatory elementcomprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99%identity to the sequence of SEQ ID NO: 16. In some embodiments, the disclosure provides use of an FXN polynucleotide construct inthe manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotideconstruct comprises the sequence set forth in SEQ ID NOs: 5, 6, 11 or 12. In some embodiments,the disclosure provides use of an FXN polynucleotide construct in the manufacture of amedicament for the treatment of FA, wherein the FXN polynucleotide construct comprises thesequence set forth in SEQ ID NO: 5. In some embodiments, the disclosure provides use of anFXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 5. In some embodiments, the disclosure provides use of an FXN polynucleotide constructin the manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotideconstruct comprises the sequence set forth in SEQ ID NO: 6. In some embodiments, thedisclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 6. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, whereinthe FXN polynucleotide construct comprises the sequence set forth in SEQ ID NO: 11. In someembodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 11. In some embodiments, the disclosure provides use of an FXN polynucleotide construct in the manufacture of a medicament for thetreatment of FA, wherein the FXN polynucleotide construct comprises the sequence set forth inSEQ ID NO: 12. In some embodiments, the disclosure provides use of an FXN polynucleotideconstruct in the manufacture of a medicament for the treatment of FA, wherein the FXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 12. In some embodiments, the disclosure provides an FXN polynucleotide construct for use in the treatment of FA. In some embodiments, the disclosure provides an FXN polynucleotideconstruct for use in the treatment of FA, wherein the human FXN coding sequence comprises thenucleotide sequence of SEQ ID NOs: 1 or 3. In some embodiments, the disclosure provides anFXN polynucleotide construct for use in the treatment of FA, wherein the human FXN codingsequence comprises the nucleotide sequence of SEQ ID NO: 1. In some embodiments, thedisclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein the human FXN coding sequence comprises a sequence with at least 80%, at least 85%, at least 90%,at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 1. In someembodiments, the disclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein the human FXN coding sequence comprises the nucleotide sequence of SEQ IDNO: 3. In some embodiments, the disclosure provides an FXN polynucleotide construct for usein the treatment of FA, wherein the human FXN coding sequence comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the nucleotide sequence of SEQ ID NO: 3. In some embodiments, the disclosure provides an FXN polynucleotide construct for usein the treatment of FA, wherein the 3’ regulatory element comprises woodchuck hepatitis viruspost-transcriptional regulatory element (WPRE3) SEQ ID NO: 9. In some embodiments, thedisclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein the3’ regulatory element comprises a sequence with at least 80%, at least 85%, at least 90%, at least95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 9. In some embodiments,the disclosure provides an FXN polynucleotide construct for use in the treatment of FA, whereinthe 3’ regulatory element comprises hFXNpA1 (SEQ ID NO: 16). In some embodiments, thedisclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein the3’ regulatory element comprises a sequence with at least 80%, at least 85%, at least 90%, at least95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 16. In some embodiments, the disclosure provides an FXN polynucleotide construct for usein the treatment of FA, wherein the FXN polynucleotide construct comprises the sequence setforth in SEQ ID NOs: 5, 6, 11 or 12. In some embodiments, the disclosure provides an FXNpolynucleotide construct for use in the treatment of FA, wherein the FXN polynucleotideconstruct comprises the sequence set forth in SEQ ID NO: 5. In some embodiments, thedisclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein theFXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 5. In someembodiments, the disclosure provides an FXN polynucleotide construct for use in the treatmentof FA, wherein the FXN polynucleotide construct comprises the sequence set forth in SEQ IDNO: 6. In some embodiments, the disclosure provides an FXN polynucleotide construct for usein the treatment of FA, wherein the FXN polynucleotide construct comprises a sequence with atleast 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence setforth in SEQ ID NO: 6. In some embodiments, the disclosure provides an FXN polynucleotideconstruct for use in the treatment of FA, wherein the FXN polynucleotide construct comprisesthe sequence set forth in SEQ ID NO: 11. In some embodiments, the disclosure provides an FXNpolynucleotide construct for use in the treatment of FA, wherein the FXN polynucleotideconstruct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or atleast 99% identity to the sequence set forth in SEQ ID NO: 11. In some embodiments, thedisclosure provides an FXN polynucleotide construct for use in the treatment of FA, wherein theFXN polynucleotide construct comprises the sequence set forth in SEQ ID NO: 12. In someembodiments, the disclosure provides an FXN polynucleotide construct for use in the treatmentof FA, wherein the FXN polynucleotide construct comprises a sequence with at least 80%, at least 85%, at least 90%, at least 95%, or at least 99% identity to the sequence set forth in SEQ ID NO: 12. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces FXN expression in one or more of the cortex, cerebellum, brainstem, spinal cord, heart,liver, or any combination thereof. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces FXN expression in the cortex. In some embodiments,treatment with an FXN polynucleotide construct described herein induces FXN expression in thecerebellum. In some embodiments, treatment with an FXN polynucleotide construct describedherein induces FXN expression in the brainstem. In some embodiments, treatment with an FXNpolynucleotide construct described herein induces FXN expression in the spinal cord. In someembodiments, treatment with an FXN polynucleotide construct described herein induces FXNexpression in the heart. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein induces FXN expression in the liver. In some embodiments, treatment with anFXN polynucleotide construct described herein induces FXN expression in the cortex,cerebellum, heart, and does not induce FXN expression in the liver. In some embodiments,treatment with the FXN polynucleotide set forth in SEQ ID NO: 5 induces FXN expression inthe cortex, cerebellum, heart, and does not induce FXN expression in the liver. In some embodiments, FXN expression is increased in a subject with FA after treatmentwith an FXN polynucleotide construct (e.g., SEQ ID NO: 5) compared to the subject beforetreatment. In some embodiments, FXN expression is increased in the cortex of a subject with FAafter treatment with an FXN polynucleotide construct compared to the subject before treatment.In some embodiments, FXN expression is increased in the cerebellum of a subject with FA aftertreatment with an FXN polynucleotide construct compared to the subject before treatment. Insome embodiments, FXN expression is increased in the brainstem of a subject with FA aftertreatment with an FXN polynucleotide construct compared to the subject before treatment. Insome embodiments, FXN expression is increased in the spinal cord of a subject with FA aftertreatment with an FXN polynucleotide construct compared to the subject before treatment. Insome embodiments, FXN expression is increased in the heart of a subject with FA after treatmentwith an FXN polynucleotide construct compared to the subject before treatment. In someembodiments, FXN expression is increased in the liver of a subject with FA after treatment withan FXN polynucleotide construct compared to the subject before treatment.In some embodiments, FXN expression is increased in a subject with FA after treatmentwith an FXN polynucleotide construct compared to an untreated subject. In some embodiments,FXN expression is increased in the cortex of a subject with FA after treatment with an FXNpolynucleotide construct compared to an untreated subject. In some embodiments, FXNexpression is increased in the cerebellum of a subject with FA after treatment with an FXNpolynucleotide construct compared to an untreated subject. In some embodiments, FXNexpression is increased in the brainstem of a subject with FA after treatment with an FXNpolynucleotide construct compared to an untreated subject. In some embodiments, FXNexpression is increased in the spinal cord of a subject with FA after treatment with an FXNpolynucleotide construct compared to an untreated subject. In some embodiments, FXNexpression is increased in the heart of a subject with FA after treatment with an FXNpolynucleotide construct compared to an untreated subject. In some embodiments, FXNexpression is increased in the liver of a subject with FA after treatment with an FXN polynucleotide construct compared to an untreated subject. In some embodiments, FXN expression is increased in the cortex by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100% compared to an untreated subject. In some embodiments, FXN expression is increased in the cerebellum by at least 5%, at least 10%, at least 20%, at least30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least100% compared to an untreated subject. In some embodiments, FXN expression is increased in the brainstem by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100% compared to an untreated subject. In some embodiments, FXN expression is increased in the spinal cord by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, atleast 80%, at least 90%, or at least 100% compared to an untreated subject. In someembodiments, FXN expression is increased in the heart by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least90%, or at least 100% compared to an untreated subject. In some embodiments, FXN expression is increased in the liver by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100% compared to an untreated subject. In some embodiments, FXN expression in tissues is measured by Western Blot (WB), immunohistochemistry (IHC), or Enzyme-Linked Immunosorbent Assay (ELISA). In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable FXN expression in a tissue by at least 5%, at least 10%, at least 20%, at least30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least 100%. In some embodiments, treatment with an FXN polynucleotide construct described hereinincreases frataxin protein expression in one or more of the cortex, cerebellum, brainstem, spinalcord, heart, liver, or any combination thereof. In some embodiments, frataxin protein expressionis increased in a subject with FA after treatment with an FXN polynucleotide construct comparedto the subject before treatment. In some embodiments, frataxin protein expression is increased ina subject with FA after treatment with an FXN polynucleotide construct compared to the subjectbefore treatment in one or more of the cortex, cerebellum, brainstem, spinal cord, heart, liver, orany combination thereof. In some embodiments, frataxin protein expression is increased in asubject with FA after treatment with an FXN polynucleotide construct compared to an untreatedsubject. In some embodiments, frataxin protein expression is increased in a subject with FA aftertreatment with an FXN polynucleotide construct compared to an untreated subject in one or moreof the cortex, cerebellum, brainstem, spinal cord, heart, liver, or any combination thereof. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable frataxin protein in a tissue by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or at least100% relative to baseline. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable frataxin protein in a tissue by at least 5%, at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least80%, at least 90%, or at least 100% in one or more of the cortex, cerebellum, brainstem, spinalcord, heart, liver, or any combination thereof relative to baseline.In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable FXN expression in a tissue within 3 days. In some embodiments, treatmentwith an FXN polynucleotide construct described herein induces detectable FXN expression in atissue within 5 days. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein induces detectable FXN expression in a tissue within 7 days. In someembodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable FXN expression in a tissue within 10 days. In some embodiments, treatment with anFXN polynucleotide construct described herein induces detectable FXN expression in a tissue forwithin days. In some embodiments, treatment with an FXN polynucleotide construct describedherein induces detectable FXN expression in a tissue within 20 days. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable FXNexpression in a tissue within 30 days. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable FXN expression in a tissue for at least 7 days. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable FXNexpression in a tissue for at least 30 days. In some embodiments, treatment with an FXNpolynucleotide construct described herein induces detectable FXN expression in a tissue for atleast 2 months. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein induces detectable FXN expression in a tissue for at least 4 months. In someembodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable FXN expression in a tissue for at least 6 months. In some embodiments, treatmentwith an FXN polynucleotide construct described herein induces detectable FXN expression in atissue for at least 8 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable FXN expression in a tissue for at least 10 months.In some embodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable FXN expression in a tissue for at least 12 months. In some embodiments, treatmentwith an FXN polynucleotide construct described herein induces detectable FXN expression in atissue for at least 14 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable FXN expression in a tissue for at least 16 months.In some embodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable FXN expression in a tissue for at least 18 months. In some embodiments, treatmentwith an FXN polynucleotide construct described herein induces detectable FXN expression in atissue for at least 20 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable FXN expression in a tissue for at least 22 months.In some embodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable FXN expression in a tissue for at least 24 months. In some embodiments, treatmentwith an FXN polynucleotide construct described herein induces detectable FXN expression in atissue for at least 30 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable FXN expression in a tissue for at least 36 months. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable frataxin protein expression in a tissue within 3 days. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable frataxinprotein expression in a tissue within 5 days. In some embodiments, treatment with an FXNpolynucleotide construct described herein induces detectable frataxin protein expression in atissue within 7 days. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein induces detectable frataxin protein expression in a tissue within 10 days. Insome embodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable frataxin protein expression in a tissue for within days. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable frataxinprotein expression in a tissue within 20 days. In some embodiments, treatment with an FXNpolynucleotide construct described herein induces detectable frataxin protein expression in a tissue within 30 days. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable frataxin protein expression in a tissue for at least 7 days. In someembodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable frataxin protein expression in a tissue for at least 30 days. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable frataxinprotein expression in a tissue for at least 2 months. In some embodiments, treatment with anFXN polynucleotide construct described herein induces detectable frataxin protein expression ina tissue for at least 4 months. In some embodiments, treatment with an FXN polynucleotide construct described herein induces detectable frataxin protein expression in a tissue for at least 6months. In some embodiments, treatment with an FXN polynucleotide construct described hereininduces detectable frataxin protein expression in a tissue for at least 8 months. In someembodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable frataxin protein expression in a tissue for at least 10 months. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable frataxinprotein expression in a tissue for at least 12 months. In some embodiments, treatment with anFXN polynucleotide construct described herein induces detectable frataxin protein expression ina tissue for at least 14 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable frataxin protein expression in a tissue for at least16 months. In some embodiments, treatment with an FXN polynucleotide construct describedherein induces detectable frataxin protein expression in a tissue for at least 18 months. In someembodiments, treatment with an FXN polynucleotide construct described herein inducesdetectable frataxin protein expression in a tissue for at least 20 months. In some embodiments,treatment with an FXN polynucleotide construct described herein induces detectable frataxinprotein expression in a tissue for at least 22 months. In some embodiments, treatment with anFXN polynucleotide construct described herein induces detectable frataxin protein expression ina tissue for at least 24 months. In some embodiments, treatment with an FXN polynucleotideconstruct described herein induces detectable frataxin protein expression in a tissue for at least30 months. In some embodiments, treatment with an FXN polynucleotide construct describedherein induces detectable frataxin protein expression in a tissue for at least 36 months. The Integrated Stress Response (ISR) is a highly conserved eukaryotic adaptation to various cellular stresses that results in phosphorylation of the α subunit of eukaryotic translationinitiation factor 2 (eIF2α). ISR activation plays a role in the development of cardiac dysfunctionvia its downstream adaptive processes; autophagy and apoptosis. Atf4, Asns, Fgf21, Gdf15 andTrib3 have all been identified as genes that are dysregulated as markers of ISR response. In someembodiments, treatment with an FXN polynucleotide construct described herein reduces theIntegrated Stress Response (ISR). In some embodiments, treatment with an FXN polynucleotideconstruct described herein reduces expression of one or more of Atf4, Asns, Fgf21, Gdf15, Trib3,or any combination thereof. In some embodiments, treatment with an FXN polynucleotideconstruct described herein reduces expression of Atf4. In some embodiments, treatment with anFXN polynucleotide construct described herein reduces expression of Asns. In someembodiments, treatment with an FXN polynucleotide construct described herein reducesexpression of Fgf21. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein reduces expression of Gdf15. In some embodiments, treatment with an FXNpolynucleotide construct described herein reduces expression of Trib3.In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in the cortexof a subject with FA compared to an untreated subject. In some embodiments, treatment with anFXN polynucleotide construct described herein reduces expression of Atf4, Asns, Fgf21, Gdf15,Trib3, or any combination thereof, by at least 5%, at least 10%, at least 20%, at least 30%, atleast 40%, or at least 50% in the cortex of a subject with FA compared to an untreated subject with FA. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in thecerebellum of a subject with FA compared to an untreated subject with FA. In someembodiments, treatment with an FXN polynucleotide construct described herein reducesexpression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, by at least 5%, atleast 10%, at least 20%, at least 30%, at least 40%, or at least 50% in the cerebellum of a subject with FA compared to an untreated subject. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in thebrainstem of a subject with FA compared to an untreated subject with FA. In some embodiments,treatment with an FXN polynucleotide construct described herein reduces expression of Atf4,Asns, Fgf21, Gdf15, Trib3, or any combination thereof, by at least 5%, at least 10%, at least20%, at least 30%, at least 40%, or at least 50% in the brainstem of a subject with FA compared to an untreated subject. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in the spinalcord of a subject with FA compared to an untreated subject with FA. In some embodiments,treatment with an FXN polynucleotide construct described herein reduces expression of Atf4,Asns, Fgf21, Gdf15, Trib3, or any combination thereof, by at least 5%, at least 10%, at least20%, at least 30%, at least 40%, or at least 50% in the spinal cord of a subject with FA compared to an untreated subject. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in the heartof a subject with FA compared to an untreated subject with FA. In some embodiments, treatmentwith an FXN polynucleotide construct described herein reduces expression of Atf4, Asns, Fgf21,Gdf15, Trib3, or any combination thereof, by at least 5%, at least 10%, at least 20%, at least30%, at least 40%, or at least 50% in the heart of a subject with FA compared to an untreated subject. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces expression of Atf4, Asns, Fgf21, Gdf15, Trib3, or any combination thereof, in the liver ofa subject with FA compared to an untreated subject with FA. In some embodiments, treatmentwith an FXN polynucleotide construct described herein reduces expression of Atf4, Asns, Fgf21,Gdf15, Trib3, or any combination thereof, by at least 5%, at least 10%, at least 20%, at least30%, at least 40%, or at least 50% in the liver of a subject with FA compared to an untreated subject. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces cardiac symptoms of FA. In some embodiments, treatment with an FXN polynucleotideconstruct described herein reduces cardiac hypertrophy in a subject with FA. In someembodiments, treatment with an FXN polynucleotide construct described herein increasesejection fraction of the heart in a subject with FA. In some embodiments, treatment with an FXNpolynucleotide construct described herein increases fractional shortening of the heart in a subjectwith FA. In some embodiments, treatment with an FXN polynucleotide construct describedherein decreases left ventricle ratio of the heart in a subject with FA. In some embodiments,treatment with the polynucleotide set forth in SEQ ID NO: 5 reduces one or more of cardiac symptoms, cardiac hypertrophy, ejection fraction, fractional shortening, or left ventricle ratio in a subject with FA. In some embodiments, treatment with an FXN polynucleotide construct described herein improves motor function in a subject with FA. In some embodiments, treatment with an FXN polynucleotide construct described herein improves muscle coordination in a subject with FA. In some embodiments, treatment with an FXN polynucleotide construct described herein improveswalking and / or balance in a subject with FA. In some embodiments, treatment with an FXNpolynucleotide construct described herein improves sensory functions in a subject with FA. Insome embodiments, treatment with an FXN polynucleotide construct described herein improvesreflexes in a subject with FA. In some embodiments, treatment with an FXN polynucleotideconstruct described herein reduces dysarthria in a subject with FA. In some embodiments,treatment with an FXN polynucleotide construct described herein improves muscle spasticity in asubject with FA. In some embodiments, treatment with an FXN polynucleotide constructdescribed herein reduces scoliosis in a subject with FA. In some embodiments, treatment with anFXN polynucleotide construct described herein improves swallowing control in a subject withFA. In some embodiments, treatment with an FXN polynucleotide construct described hereinreduces hearing and / or vision loss in a subject with FA. In some embodiments, treatment with anFXN polynucleotide construct described herein reduces fatigue in a subject with FA. In someembodiments, treatment with the polynucleotide set forth in SEQ ID NO: 5 improves motor function, improves muscle coordination, improves walking and / or balance, improves sensory functions, improves reflexes, reduces dysarthria, improves muscle spasticity, reduces scoliosis, improves swallowing, reduces hearing and / or vision loss, reduces fatigue, or any combination thereof in a subject with FA. In some embodiments, treatment with an FXN polynucleotide construct described hereinimproves survival of a subject with FA. In some embodiments, treatment with the polynucleotide set forth in SEQ ID NO: 5 improves survival in a subject with FA. In some embodiments, the methods of the disclosure may comprise administering an effective amount of a pharmaceutical composition comprising the FXN polynucleotide construct described herein to a subject in need thereof. In some embodiments, the effective amount is at least 1 x 108viral genomes per dose. In some embodiments, the effective amount is at least 5 x 108viral genomes / dose, 7.5 x 108viral genomes / dose, at least 1 x 109viral genomes / dose, at least 2.5 x 109viral genomes / dose, or at least 5 x 109viral genomes / dose. In some embodiments, the effective amount is at least 1 x 1011viral genomes / kg patient weight, at least 5 x 1011viral genomes / kg, at least 1 x 1012viral genomes / kg, at least 5 x 1012viral genomes / kg, at least 1 x 1013viral genomes / kg, at least 1 x 1014viral genomes / kg, or at least 5 x 1014. In some embodiments, the rAAV is dosed based upon brain weight rather than by bodyweight. In some embodiments, the rAAV dose is considered a low dose and is particularlybeneficial for a nerve or muscle related indication.In some embodiments, the rAAV is administered intravenously. In some embodiments, the rAAV is administered intrathecally. In some embodiments, the rAAV is administered by intracerebral ventricular injection. In some embodiments, the rAAV is administered by intracisternal magna administration. In some embodiments, the rAAV is administered intravenously (IV). In some embodiments, the rAAV is administered by Deep Cerebellar Nuclei (DCN) injection. In various embodiments a method of treating FA and related disorders in a subject is disclosed, wherein the method comprises administering to the subject an effective amount of any of the polynucleotide constructs described herein, or the vectors, or the rAAV comprising the vectors, or the virion, or any pharmaceutical composition comprising any of these elements, as described herein. Additionally, in certain embodiments, constructs and rAAVs as described herein can be used as a gene therapy to increase mitochondrial iron transport and or respiration in a subject in need thereof. Kits In some embodiments, the disclosure provides a kit comprising a therapeutic FXNpolynucleotide construct comprising: a promoter fragment; an optional non mammalian based miRNA regulatory element and at least one cognate miRNA binding site; a human FXN coding sequence; a 3’ regulatory element; and a polyadenylation signal. In some embodiments, a kit includes a therapeutic FXN polynucleotide constructdescribed herein, and instructions for use. The kits may comprise, in a suitable container, therapeutic FXN polynucleotide construct described herein, one or more controls, and various buffers, reagents, enzymes and other standard ingredients well known in the art. The container can include at least one vial, well, test tube, flask, bottle, syringe, or other container means, into which a therapeutic FXN polynucleotide construct described herein may be placed, and in some instances, suitably aliquoted. Where an additional component is provided, the kit can contain additional containers into which this component may be placed. The kits can also include a means for containing a therapeutic FXN polynucleotide construct described herein and any other reagent containers in close confinement for commercial sale. Such containers may include injection or blow-molded plastic containers into which the desired vials are retained. Containers and / or kits can include labeling with instructions for use and / or warnings. In some embodiments, a kit comprises FXN polynucleotide construct described herein, and a pharmaceutically acceptable carrier, or a pharmaceutical composition comprising the FXN polynucleotide construct described herein, and instructions for treating a subject with FA. In some embodiments,a kit comprises an FXN polynucleotide construct herein, and a pharmaceutically acceptablecarrier, or a pharmaceutical composition comprising AAV capsid fusion protein comprising a TfR1-targeted VHH nanobody described herein, and instructions for administering the FXN polynucleotide construct described herein to a subject in need thereof, alone or in combination with another agent, for treating a subject with FA.EXEMPLARY EMBODIMENTSIn some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatoryelement, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatoryelement, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 miRNA regulatory element, a 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence, a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises apromoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a hFXNpA13’ regulatory element (SEQ ID NO: 16), and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises apromoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatory element, and an SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, anintron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNAregulatory element, 3’ untranslated region (3’UTR) containing three binding sites for theEXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatoryelement, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, a hFXN coding sequence containing an intron 1fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. In someembodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognatemiRNA binding site, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatoryelement, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA bindingsite, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a hFXNpA13’ regulatoryelement (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXNpolynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatory element, andan SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a 3’ regulatory element, and anSV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing anintron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and a polyadenylation signal. Insome embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 miRNA regulatory element, a 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence, a hFXNpA13’ regulatoryelement (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXNpolynucleotide construct comprises a promoter fragment, an EXACT1 miRNA regulatory element, a 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence, a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 miRNA regulatory element, a 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence, a 3’ regulatory element, and anSV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an intron-less hFXN coding sequence (SEQ ID NO: 1), a hFXNpA13’ regulatory element(SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotideconstruct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, theFXN polynucleotide construct comprises a promoter fragment, an optional non-mammalianmiRNA regulatory element, at least one cognate miRNA binding site, an hFXN coding sequencecontaining an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element (SEQ ID NO: 9),and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, andan SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotideconstruct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, a hFXN coding sequence containing an intron1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and an SV40 polyadenylation signal (SEQID NO: 10). In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a hFXNpA13’ regulatory element (SEQ ID NO: 16), anSV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotideconstruct comprises a promoter fragment, an optional non-mammalian miRNA regulatory element, at least one cognate miRNA binding site, an FXN coding sequence, a WPRE3 regulatoryelement (SEQ ID NO: 9), an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises anhFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element (SEQ ID NO: 8), 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXNcoding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises aCMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA,an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’ regulatory element, and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and aan SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXNpolynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing anintron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and an SV40 polyadenylation signal(SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises apromoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an hFXN codingsequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element (SEQID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises apromoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an hFXN codingsequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element (SEQID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and apolyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing anintron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and an SV40 polyadenylation signal(SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises apromoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXNcoding sequence (SEQ ID NO: 1), a 3’ regulatory element, and an SV40 polyadenylation signal(SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), anEXACT1 non-mammalian miRNA regulatory element), 3’ untranslated region (3’UTR)containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an FXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non- mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ ID NO: 9), and a polyadenylation signal. In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, andan SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXNpolynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence(SEQ ID NO: 1), a 3’ regulatory element, and an SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXNcoding sequence containing an intron 1 fragment (SEQ ID NO: 3), a 3’ regulatory element, and anSV40 polyadenylation signal (SEQ ID NO: 10).. In some embodiments, the FXN polynucleotideconstruct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non- mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three bindingsites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a 3’regulatory element, and an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and anSV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotideconstruct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA,an hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3regulatory element (SEQ ID NO: 9), and an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and anSV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotideconstruct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA,an hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3regulatory element (SEQ ID NO: 9), and an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and an SV40 polyadenylation signal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises a promoter fragment, an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ IDNO: 9), and an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises a CMV / CBA promoter fragment (SEQ ID NO: 7), a hFXN coding sequence containing an intron 1 fragment(SEQ ID NO: 3), a WPRE3 regulatory element (SEQ ID NO: 9), and an SV40 polyadenylationsignal (SEQ ID NO: 10). In some embodiments, the FXN polynucleotide construct comprises CMV / CBA promoter fragment (SEQ ID NO: 7), ), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a hFXNcoding sequence containing an intron 1 fragment (SEQ ID NO: 3), a WPRE3 regulatory element(SEQ ID NO: 9), and an SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises CMV / CBA promoter fragment (SEQ ID NO: 7), an EXACT1 non-mammalian miRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, an intron-less hFXN coding sequence (SEQ ID NO: 1), a WPRE3 regulatory element (SEQ ID NO: 9), andan SV40 polyadenylation signal (SEQ ID NO: 10).In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an hFXN enhancer (SEQ ID NO: 15), a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a 5’ hFXN UTR (SEQ ID NO: 14). In some embodiments, the FXN polynucleotide construct comprises an hFXNP882 promoter fragment (SEQ ID NO: 13), an hFXN enhancer (SEQ ID NO: 15), an EXACT1 non-mammalianmiRNA regulatory element, 3’ untranslated region (3’UTR) containing three binding sites for theEXACT1 miRNA, a hFXN coding sequence containing an intron 1 fragment (SEQ ID NO: 3), a hFXNpA13’ regulatory element (SEQ ID NO: 16), and a 5’ hFXN UTR (SEQ ID NO: 14). EXAMPLES Below are examples of specific embodiments for carrying out the present invention. The examples are offered for illustrative purposes only and are not intended to limit the scope of thepresent invention in any way. Efforts have been made to ensure accuracy with respect to numbersused (e.g., amounts, temperatures, etc.), but some experimental error and deviation should, of course, be allowed for. The practice of the present invention will employ, unless otherwise indicated, conventional methods of protein chemistry, biochemistry, recombinant DNA techniques and pharmacology, within the skill of the art. Such techniques are explained fully in the literature. Example 1 A. Design of gene therapy constructs for the treatment of Friedreich AtaxiaTherapeutic gene therapy constructs to treat Friedreich Ataxia (FA) were designed to express constrained levels of wild-type human frataxin, regulated either by an EXACT circuit,endogenous FXN regulatory elements, or both (Fig. 3). All constructs express full-length wild-type frataxin protein (SEQ ID NO: 2). In cells, full-length frataxin is trafficked to the mitochondria before undergoing processing by mitochondrial processing proteins to form functional mature frataxin. Gene therapy constructs often contain intron-less transgene sequences. The intron-less coding sequence of wild-type human FXN is described in SEQ ID NO: 1. An analysis of human FXN using the UCSC Genome Browser analysis demonstrated that most important FXNendogenous regulatory elements are located in exon 1 and intron 1. Therefore, within the FXNtransgene in the test gene therapy constructs, a 1.3 kb fragment of human FXN intron 1 was included between the sequence of FXN exons 1 and 2, retaining the endogenous splice donor and acceptor sequences. The hFXN transgene sequence that contains this intron 1 fragment is named hFXN_in1 (SEQ ID NO: 3). To ensure that including intron 1 in the transgene sequence did not negatively affect transgene expression, plasmids were generated that expressed wild-type human FXN as an intron- less coding sequence, or with intragenic intron sequence at endogenous FXN intron positions 1, 2, 3 or 4. Each intron tested comprised a fragment of endogenous human FXN intron sequence, at the respective intron positions. Endogenous splice donor and acceptor sequences were retained in each construct. In each plasmid, the reporter mNeonGreen was fused to hFXN and a second expression cassette in the plasmid allowed a separate fluorescent marker (mRuby) to be measured and used to monitor the level of construct delivered to each cell (surrogate for dose). Including introns 1, 2 or 4 in the hFXN transgene sequence had a mildly positive impact on frataxin- mNeonGreen expression, whereas including intron 3 in the hFXN transgene sequence had a mildlynegative impact on frataxin-mNeonGreen expression (Fig. 2). This data supported the use of thehFXN_in1 transgene sequence (SEQ ID NO: 3) in construct design (Fig. 3).B. EXACT regulation of frataxin expression in vitro Figure 1 illustrates that feed-forward control of dosage sensitivity can be achieved in the dosage sensitive FXN gene using the non-mammalian EXACT mechanism (as described in WO / 2022 / 003348). Plasmids were generated that expressed the EXACT1 miRNA and wild-type human FXN in which the reporter mNeonGreen was fused to hFXN. A second expression cassette in the plasmid allowed a separate fluorescent marker (mRuby) to be measured and used to monitor the level of construct delivered to each cell (surrogate for dose). The 3’UTR contained 3 fully complementary miRNA binding sites for EXACT1 miRNA. An ‘unregulated hFXN’ plasmidwithout the EXACT feedforward mechanism was also generated as a control (Fig. 1). Humanembryonic kidney 293 cells (HEK 293) were transfected with 100 µg of each plasmid using Lipofectamine. After 48 hrs, cells were collected, and the level of transgene expression was assessed by flow cytometry, in which levels of mRuby (transfection efficiency) and mNeonGreen (hFXN) were measured. The plasmid expressing human FXN under EXACT1 feedforward regulation showed reduced protein expression compared to the plasmid with no EXACT circuit (unregulated hFXN control). The dampening effect of the feed-forward element increased as the amount of construct delivered increased, suggesting that the control elements can mitigate toxicity without impeding expression of the gene at a therapeutic level. EXACT-regulated constructs NG347 (SEQ ID NO: 5) and NG348 (SEQ ID NO: 6) are comprised of the CMV (cytomegalovirus) enhancer, a chicken beta-actin (CBA) promoter, a MINX intron containing a non-mammalian miRNA (EXACT1), an hFXN DNA coding sequence, a 3’ untranslated region (3’UTR) containing three binding sites for the EXACT1 miRNA, a shortened Woodchuck Hepatitis Virus Posttranscriptional Regulatory Element (WPRE3), and a simian vacuolating virus 40 polyadenylation signal (SV40pA). NG347 comprises the hFXN_in1 transgene sequence (SEQ ID NO: 3 and SEQ ID NO: 5); NG348 comprises the intron-less hFXN transgene sequence (SEQ ID NO: 1 and SEQ ID NO: 6). The maps of NG347 and NG348 are shown in Figure 3. NG346 (SEQ ID NO: 4) comprises the promoter, transgene and 3’UTR sequences described in NG347 (SEQ ID NO: 5), but without the EXACT feedforward circuit (no EXACT1 miRNA scaffold within the MINX intron, and no EXACT1 miRNA binding sites within the 3’UTR). This construct acts as a control of unregulated transgenic frataxin expression. The map of NG346 is shown in Figure 3. Constructs NG349 (SEQ ID NO: 11) and NG350 (SEQ ID NO: 12) are comprised of human endogenous regulatory elements to drive and regulate FXN expression. NG349 and NG350 both comprise a fragment of the endogenous human FXN promoter, named hFXNP882 (SEQ ID NO: 13), and the 5’UTR (SEQ ID NO: 14) to drive expression of hFXN. The endogenous Kozak sequence is maintained. In addition, a putative enhancer element of human FXN (SEQ ID NO:15)was placed upstream of the promoter in NG349 and NG350. Constructs NG349 and NG350comprise the hFXN_in1 transgene sequence (SEQ ID NO: 3), adding additional endogenous regulatory elements harbored within intron 1, and expressing wild-type human FXN. Constructs NG349 and NG350 also contain an endogenous 3’UTR sequence, named hFXNpA1 (SEQ ID NO: 16), comprising two fragments of the endogenous human FXN 3’UTR, including a putative regulatory element and the distal polyA signal predicted to be used predominantly by FXN transcripts. In addition to these endogenous regulatory elements, NG350 also contains an EXACT circuit, comprising an EXACT1-miRNA-expressing scaffold within the intron 1 sequence, and three fully complementary binding sites to EXACT1 miRNA in the 3’UTR. The maps of NG349 and NG350 are shown in Figure 3. All constructs (NG346 – SEQ ID NO: 4; NG347 – SEQ ID NO: 5; NG348 – SEQ IDNO: 6; NG349 – SEQ ID NO: 11; and NG350 – SEQ ID NO: 12) were flanked by AAV2 ITRsand packaged into single-stranded AAV9 capsids. The products comprised adeno-associated viral vector type 9 (AAV9) capsids packaged with the single-stranded adeno-associated virus (AAV) genome comprising wild-type adeno-associated virus type 2 (AAV2) inverted terminal repeats (ITRs). Recombinant AAV9 products were generated using a Baculovirus Expression VectorSystem based process, using Spodoptera frugiperda (Sf9) insect cells, by Virovek Inc. (Hayward,CA, USA) using their standard AAV production process. The final product was formulated in PBS containing 0.001% Poloxamer 188. Vector concentration was determined using ddPCR.Additionally, sequencing and CDMS data from the preparations confirm the expected sequencesand packaging abilities of the recombinant products. Example 2In vivo study of frataxin expressionAAV9 vectors expressing feed-forward FXN constructs were delivered to wild-type mice maintained on a mixed CBA / C57 background. Single-stranded AAV9 expressing regulated or unregulated FXN was injected bilaterally into the brains of postnatal day (P)0 / 1 mice byintracerebroventricular (ICV) administration, at a dose of 3 × 1011 vg per mouse (Fig. 4). Controlinjections used the same diluent without vector (vehicle control). Injected pups were returned tothe home cage and monitored until 8 weeks of age, or until reaching their humane endpoint. Micewere assigned into groups with an n=9 according as set forth in Table 1. Table 1. Treatment groups for the in vivo study of frataxin expression TreatmentGenotype Vector ConstructDose n per group group type (vg / mouse) 1WT Vehicle - - 92 WT AAV9-NG346 Unregulated 3 x 1011 93 WT AAV9-NG347 EXACT3 x 10119 regulation 4WT AAV9-NG348 EXACT3 x 10119 regulation 5WT AAV9-NG349 Endogenous3 x 10119 regulatory elements 6WT AAV9-NG350 Endogenous3 x 10119 regulatory elements + EXACT regulation At 4-5 weeks post-injection, overt toxicity was observed in animals from a single treatment cohort; mice treated with AAV9-NG346, which expresses unregulated human frataxin. No overt toxicity was observed in any other treatment group at this time point. Age-matched samples from all treatment groups, including the vehicle control group, were collected to allow cross-comparison across groups at this time point. Tissues were collected and processed to isolate DNA, total RNA, and protein. Analysis of DNA isolated from the tissues of animals from all treatment groups at 4 weeks of age indicated that vector biodistribution was comparable across all treatment groups (Fig.5). Analysis of frataxin expression by western blot indicated that mature FXN was detected in thecortex, cerebellum, heart, and liver in groups treated with AAV9-NG346, AAV9-NG347, AAV9-NG348 or AAV9-NG349 (Fig. 6). In all tissues, significant levels of frataxin overexpression weredetected in animals treated with AAV9-NG346, the unregulated construct (Figure 6). In addition, Integrated Stress Response markers were observed to be highly elevated in the hearts of animalstreated with AAV9-NG346, the unregulated construct (Fig. 7). The Integrated Stress Response(ISR) is a highly conserved eukaryotic adaptation to various cellular stresses that results inphosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). ISR activationplays a role in the development of cardiac dysfunction via its downstream adaptive processes;autophagy and apoptosis. Atf4, Asns, Fgf21, Gdf15 and Trib3 have all been identified as genes thatare dysregulated as markers of ISR response. Analysis of total RNA isolated from the heart tissues of animals from all treatment groups at 4 weeks of age showed that all five of these genes were significantly upregulated in the hearts of animals treated with AAV9-NG346, the unregulatedconstruct (Fig. 7), indicating ISR activation in this cohort. No increase in ISR markers wasobserved in the hearts of animals treated with AAV9-NG347, AAV9-NG349 or AAV9-NG350compared to levels in the hearts of vehicle-treated animals (Fig. 7).At the study endpoint (8 weeks post-injection), all animals in non-AAV9-NG346 treatment groups survived (n=6 per group), with no evidence of toxicity. Analysis of DNA isolated from the tissues of animals from all treatment groups at 8 weeks of age indicated that vector biodistribution was comparable across all treatment groups, and comparable with the data collectedat 4 weeks post-transfection (Fig.8). Analysis of frataxin expression by western blot indicated thatmature FXN was detected in the cortex, cerebellum and heart in groups treated with AAV9-NG347, AAV9-NG348, AAV9-NG349 or AAV9-NG350 at 8 weeks post-injection (Fig. 9A). Nomature frataxin signal was detected in the liver at this time point (Fig. 9B). A baseline endogenousfrataxin signal was detected in cerebellum & heart at 8-weeks, but not in the cortex or liver (Fig.9B). When normalized to endogenous frataxin levels in vehicle-treated animals, frataxin levelsfrom NG347 & NG349 are detected at levels higher than endogenous frataxin in the cerebellum and heart, but in a range of expression expected to be well-tolerated and efficacious. Animals treated with AAV9-NG348, which comprises the intron-less hFXN transgene sequence, show elevated levels of mature frataxin at 8 weeks post-injection, in contrast to the other treatmentgroups, which comprise the intron 1 containing hFXN transgene sequence, hFXN_in1 (Fig. 9C).Analysis of total RNA isolated from the tissues of animals from all treatment groups at 8 weeks ofage indicated that transgenic human FXN mRNA could be readily detected above endogenouslevels of mouse Fxn mRNA, in all tissues tested (Fig. 10). Relative differences in the transgenicmRNA levels (Fig. 10) and protein levels (Fig. 9A-C) can be attributed to differential regulationin the constructs; the presence or absence of endogenous regulatory elements, difference in Kozak strength, and the presence or absence of EXACT regulation. Analysis of total RNA isolated fromthe heart tissues of animals from all treatment groups at 8 weeks of age showed that no significantchange in ISR marker expression was observed compared to vehicle-treated controls (Fig. 11). Inthe 8-week samples tested, two ISR markers, Fgf21 and Gdf15, could not be analyzed due toinsufficient amplification. Example 3Pilot study to assess direct delivery of transgenic frataxin to the Deep Cerebellar Nuclei(DCN) in wild-type rats Pilot studies to assess direct delivery of transgenic frataxin to the Deep Cerebellar Nuclei(DCN) in wild-type rats AAV9-NG347 was delivered to the Deep Cerebellar Nuclei (DCN) ofwild-type Long Evans rats to assess if EXACT-regulated constructs afford expression with safetywhen delivered directly into the parenchyma (Fig. 12). Six wild-type Long Evans rats aged 9-10 weeks were used in this study (4x male, 2x female), and AAV9-NG347 was injected into the DCNs bilaterally using coordinates previously established. In each rat, the left hemisphere was dosed with vehicle / PBS, and the right hemisphere was dosed with either a low (4 × 109vg) or high (4 ×1010 vg) dose of AAV9-NG347 in a 350 µl dosing volume (Table 2).Table 2. Treatment groups for the direct DCN delivery of AAV9-NG347 in WT ratsTreatment n per Genotype Hemisphere Vector Dose (vg)group group Left Vehicle -1 WT 93 Right AAV9-NG347 4.0 x 10Left Vehicle -2 WT 103 Right AAV9-NG347 4.0 x 10All rats tolerated DCN injections and survived to the study endpoint with no adverse effects. Whole brains were perfused, immersion fixed for 48 hours, then washed in PBS beforeprocessing (6 sections per brain embedded in two blocks) and stained for H&E, GFAP, Iba1,Luxol fast blue, and frataxin. Histopathological evaluation did not reveal any AAV9-NG347-related findings despite the presence of frataxin in the stained sections. The microscopic neural findings were assessed 6 weeks following test article administration. Microscopic findings were localized to the injection site (DCN) and cerebellar cortex overlying the DCN. The most common findings were microgliosis in DCN and an injection track delineated by a narrow column of astrocytosis and microgliosis that extended through the entire cerebellar cortex on one side of the cerebellum just lateral to the midline. All findings were of minimal severity and were interpreted as unavoidable procedure-related findings rather than test article-related effects. Therefore, direct delivery of frataxin to the DCN was well tolerated at both doses. Example 4 Study to assess EXACT-regulated frataxin expression in wild-type (WT) mice An in vivo vector biodistribution and frataxin expression study was conducted to assessthe delivery of two vectors expressing human frataxin (NG346 and NG347) when delivered directly to the brains of WT mice with AAV9 capsids. Vectors were administered to WT micevia intracerebroventricular (ICV) injection at postnatal day P1 at a dose level of 1.0 × 1011vg / mouse. A vehicle-treated control group was included in the study and each group contained 3animals (Table 3).Table 3. Treatment groups for the study of frataxin expression in WT mice Treatment Genotype Vector Dose (vg / kg) n per groupgroup 1WT Vehicle - 32 WT AAV9-NG346 1.0 x 1011 33 WT AAV9-NG347 1.0 x 1011 3Mice were sacrificed at 3 weeks of age (3 weeks post-dosing) for biochemical evaluationincluding vector biodistribution and frataxin expression (ELISA). Results showed that in WTmice treated with AAV9-NG346 or AAV9-NG347, vector DNA and transgenic human frataxin were detected in all target tissues. For all vectors, assessment of vector DNA at 3 weeks of age showed high levels of vector in the cortex, and lower levels in the cerebellum, heart and liver (Fig. 13). Results were consistent with previous studies in which AAV9 was administered by ICV delivery to neonatalmice (postnatal days 0-2). Expression of transgenic human frataxin, quantified by ELISA,showed a similar pattern, with frataxin levels highest in the cortex in each treatment group, lower in cerebellum and heart, and lowest in liver (Fig. 14). Levels of transgenic human frataxin were highest in NG346-treated mice in all tissues tested, and lower in NG347-treated mice. This result reflects the ‘unregulated’ frataxin from NG346 and ‘regulated’ frataxin expression from NG347. Robust, near-endogenous levels of human frataxin were detected in the cerebellum of NG347- treated mice, a region of the brain known to be involved in the pathophysiology of FA. Overall, this study shows that direct brain delivery of a 1.0 × 1011vg / mouse dose of AAV9-NG347 was well-tolerated and provides levels of vector biodistribution and frataxin expression in the CNS that would be expected to be efficacious in a CNS disease mouse model of FA. At the same dose, AAV9-NG346 provides much higher levels of frataxin expression that could potentially lead to transgene-related toxicities. This study supports the utility of EXACT regulation to constrain transgenic frataxin expression to safe and efficacious levels. Example 5Safety of systemically delivered AAV9-NG347 in wild-type miceAn in vivo study was conducted in WT mice to assess vector biodistribution andtransgenic protein expression in the heart and liver from a single vector expressing regulated human frataxin (NG347) when delivered systemically with AAV9 capsids. Vectors were administered to WT mice via intravenous (IV) injection at postnatal day P34 at a dose level of 1.0 × 1013vg / kg or 1.0 × 1014vg / kg. NG347 was packaged in AAV9 capsids. A vehicle-treated control group was included in the study and each group contained 6-7 animals. Note that in the high-dose AAV9-NG347 treatment group, one animal was analyzed for vector genomes but not for Actb, so no vg / diploid genome value was obtained for this animal. Mice were sacrificed at 9weeks of age (4 weeks post-dosing) for biochemical evaluation. All mice in the study, vehicle- ortest-article-treated, survived to the end of the study with no in-life adverse observations noted.No differences in survival or bodyweight were observed between groups (data not shown).In WT mice treated with either dose of AAV9-NG347, vector genomes and transgenic human frataxin was detected in all target tissues. Assessment of vector DNA at 9 weeks of age showed widespread biodistribution to the heart and liver, with highest levels in the liver (Fig. 15). Expression of transgenic human frataxin, quantified by ELISA, showed a similar pattern, with frataxin levels highest in the liver at both doses (Fig. 16). In the heart, transgenic frataxin was expressed in a dose-dependent manner; very low levels of human frataxin were detected in the hearts of the low-dose treatment group, but near endogenous levels of frataxin were detected in the hearts of mice in the high-dose treatment group (Fig.16). Analysis of integrated stress response (ISR) marker gene expression in the heart, quantified by qPCR, showed no elevation of gene expression in NG347 treatment groups relative to vehicle-treated controls (Fig.17). This indicates that the integrated stress response was not activated in the hearts of NG347-treated mice and agrees with the observation that levels of transgenic human frataxin were not excessive in the hearts of NG347-treated mice at either dose.AAV9-NG347 did not produce degenerative findings in the heart or liver at either dose Based on these findings, increased doses of AAV9-NG347 and other vectors of interest were assessed in the MCK-KO efficacy study. Example 6 Efficacy in the MCK-KO cardiac mouse model of FA after systemic delivery of AAV9- NG347 An in vivo efficacy study was conducted to assess the therapeutical potential of anEXACT-regulated vector expressing human frataxin to ameliorate phenotypes in the hearts of a murine disease model of Friedreich’s Ataxia (FA). In mouse models of FA, the most disease- relevant cardiac phenotypes are recapitulated in the conditional Muscle Creatine Kinase knockout (MCK-KO) model (Puccio et al., 2001). In this model, early cardiomyopathy and heart hypertrophy leads to a progressive decline in cardiac function and early death. Vectors packaged in AAV9 capsids were administered systemically to MCK-KO mice via intravenous (IV) injection at postnatal day P35 at a dose level of 5.0 × 1013vg / kg (‘low dose’) or 1.5 × 1014vg / kg (‘high dose’). Three vectors were assessed: AAV9-NG347, AAV9- NG349 and AAV9-NG350. Vehicle-treated WT and MCK-KO control groups were alsoincluded in the study. The study design is described in Fig. 18 and Table 4. Within eachtreatment group (n=16 per group total), tissues were collected for biochemical evaluation at 10 weeks of age (5 weeks post-dosing) from a ‘necropsy’ cohort (n=6 per group); the remaininganimals in each treatment group (n=10 per group) formed ‘survival’ cohorts and were allowed tosurvive until death or humane endpoint, up to 30 weeks of age (Fig.18). The expected median survival of untreated MCK-KO mice was ~11weeks of age. Table 4. Treatment groups for MCK-KO mouse model Treatment n per group Genotype Vector Dose (vg / kn per group groupg)(necropsy 10 weeks) (survival) 1WT Vehicle - 6 102 MCK-KO Vehicle - 6 103 MCK-KO AAV9-NG347 5.0 x 10136 104 MCK-KO AAV9-NG349 5.0 x 1013 6 105 MCK-KO AAV9-NG350 5.0 x 10136 106 MCK-KO AAV9-NG347 1.5 x 10146 107 MCK-KO AAV9-NG349 1.5 x 10146 108 MCK-KO AAV9-NG350 1.5 x 10146 10At 10 weeks of age, tissues were collected from all animals in the necropsy cohorts for biochemical evaluation. In mice treated with either dose of AAV9-NG347, AAV9-NG349 or AAV9-NG350, vector genomes and transgenic human frataxin were detected in all target tissues. For all vectors, assessment of vector DNA at 10 weeks of age showed widespread, dose- dependent biodistribution to the heart and liver, with highest levels in the liver (Fig. 19). Results were consistent with published studies of AAV9 vector biodistribution. Expression of transgenic human frataxin in the heart, quantified by ELISA, was highest in mice treated with AAV9-NG347, lower in mice treated with AAV9-NG349, and lowest in mice treated with AAV9-NG350 (Fig. 20). As vector biodistribution was deemed to be consistent across different treatment groups (with respect to dose), these different frataxin levels likely reflect the different promoters, and / or presence of EXACT regulation in the different constructs. Similar patterns of expression were observed in the liver. In both heart and liver,frataxin expression from NG349, which contains endogenous human FXN regulatory elementsbut is not EXACT-regulated, increased in a dose-dependent manner (Fig.20). Frataxin expression from EXACT-regulated NG347 and NG350 either increased expression in a more modest manner, or did not increase expression at the higher dose, indicating that regulation of frataxin expression is more profound (Fig.20). In the hearts of animals in the necropsy cohorts, frataxin expression was also detected by immunohistochemical staining (Fig. 21), confirming the results obtained by ELISA analysis. At the 10-week necropsy, heart weights and body weights were measured and a heart weight : body weight ratio determined for animals across all treatment groups. At 5 weeks post-injection, cardiac hypertrophy, a key phenotype in the MCK-KO model of FA, was ameliorated in all treatment groups receiving AAV9-NG347, AAV9-NG349 or AAV9-NG350 at either dose (Fig. 22), showing that recapitulation of any frataxin expression in the heart (absent in the hearts ofuntreated MCK-KO mice, as shown in Fig. 20 and Fig. 21) provided some phenotypicimprovement. In the survival cohorts (n=10 per treatment group), survival was extended in every treatment group receiving AAV9-NG347, AAV9-NG349 or AAV9-NG350, at either dose, compared to the MCK-KO + vehicle control group which had a median survival of ~11 weeks (Fig.23). The greatest survival benefit was observed in the high-dose AAV9-NG347 treatment group, with 40% of animals surviving to the study endpoint of 30 weeks (Fig.23). Body weights were also improved in all treatment groups relative to MCK-KO + vehicle controls, with the high-dose AAV9-NG347 treatment group most closely tracking the WT controls throughout the study (data not shown). Cardiac phenotypes were assessed by echocardiogram (ECHO) at 4 weeks of age, toestablish baseline recordings before dosing, and then at 9, 12, 18 and 23 weeks (4-, 7-, 13- and18-weeks post-dosing, respectively). Key cardiac phenotypes such as ejection fraction and fractional shortening were improved in all treatment groups at all timepoints compared to the MCK-KO + vehicle control group, with the high-dose AAV9-NG347 treatment group tracking most closely to the WT control group throughout (Fig. 24A-B). The ratio of left ventricle mass to body weight was also improved in all treatment groups relative to the MCK-KO + vehiclecontrol group, and indistinguishable from WT controls (Fig. 24 C).Overall, this study shows that a high dose of AAV9- NG347 was efficacious in the MCK-KO mouse model of FA, significantly extending survival from 10.1 to 26.4 weeks (based on median survival in the MCK-KO + vehicle group and the MCK-KO + AAV9-NG3471.5 × 1014vg / kg treatment group; Fig. 23), and precluding emergence of overt cardiac phenotypes. In theWT mouse study discussed above, a high dose of AAV9- NG347 (1.0 × 1014 vg / kg) was alsofound to be safe and well-tolerated in WT mice, with no overt toxicities observed, nohistopathological abnormalities, and no elevated ISR markers. Importantly for FA, a dosage- sensitive condition, AAV9-NG347-derived frataxin expression in the heart and liver was constrained to demonstrate that NG347 has the potential to achieve efficacy in FA without expressing toxic levels of protein. Example 7Safety of systemically delivered AAV-PHP.eB-hFXN in wild-type micePrior to performing an efficacy study in the PV-KO mouse model, an in vivo study wasconducted in wild-type (WT) mice to assess vector biodistribution and transgene expression in the CNS from three vectors expressing human frataxin (NG347, NG349 and NG350) when delivered systemically with a CNS-penetrant capsid (AAV-PHP.eB). Vectors were administered to WT mice via intravenous (IV) injection at postnatal day P42 at a dose level of 2.0 × 1013vg / kg (Table 5). Table 5. Treatment groups for the safety of systemically delivered frataxin in WT mice Treatment Genotype Vector Dose (vg / kg) n per groupgroup 1WT Vehicle - 52 WT AAV-PHP.eB-NG347 2.0 x 1013 53 WT AAV-PHP.eB-NG349 2.0 x 1013 54 WT AAV-PHP.eB-NG350 2.0 x 1013 5Vectors were packaged in AAV-PHP.eB capsids to efficiently target the CNS. A vehicle-treated control group was included in the study and each group contained 5 animals. Mice were sacrificed at 9 weeks of age (3 weeks post-dosing) for biochemical evaluation. All mice in thestudy, vehicle- or test-article-treated, survived to the end of the study with no in-life adverseobservations noted. No differences in survival or bodyweight were observed between groups (data not shown). Results showed that in WT mice treated with AAV-PHP.eB-NG347, AAV-PHP.eB- NG349, or AAV-PHP.eB-NG350, vector DNA and transgenic human frataxin were detected in all target tissues. For all vectors, assessment of vector DNA at 9 weeks of age showed widespread biodistribution in CNS, across various brain regions, with highest levels in the cortex and robust levels in the cerebellum and spinal cord, regions of the brain known to be involved in FA pathophysiology (Fig. 25). Lower levels of vector DNA were observed in peripheral tissues, with the lowest levels in the heart. Results were consistent with published studies of AAV- PHP.eB vector biodistribution. Expression of transgenic human frataxin, quantified by ELISA, showed a similar pattern, with frataxin levels highest across brain regions in each treatment group, lower in liver, and only trace levels in heart (Fig. 26). Levels of transgenic human frataxin were highest in NG347-treated mice in all tissues tested (except for spinal cord), lower in NG349-treated mice, and lowest in NG350-treated mice, reflecting differences in transgene expression, translation efficiency and regulation between vectors. Robust levels of human frataxin were detected in the cerebellum and spinal cord of NG347 and NG349-treated mice, regions of the brain known to be involved in FA pathophysiology. Importantly for FA, a dosage- sensitive condition, even in highly transduced tissues such as the cortex, transgene-derived frataxin levels were constrained to levels that had the potential to be safe and efficacious in a mouse model of FA. Immunohistochemistry analysis of frataxin in the brain and spinal cords of animals in all treatment groups broadly aligned with the results obtained by ELISA. AAV-PHP.eB-NG347 and NG349 provided significantly increased frataxin expression to the brain and spinal cord, in terms of staining intensity, frataxin area, and percent positive nuclei. AAV-PHP.eB-NG347 provided higher frataxin expression in the cerebellum, whereas AAV-PHP.eB-NG349 provided increased staining intensity in the DCN, and spinal cord (data not shown). Example 8 Efficacy and safety in the PV-KO CNS mouse model of FA after systemic delivery of AAV- PHP.eB-NG347 An in vivo efficacy study was conducted to assess the therapeutical potential of anEXACT-regulated vector expressing human frataxin to ameliorate phenotypes in the central nervous system (CNS) of a murine disease model of Friedreich’s Ataxia (FA). In mouse modelsof FA, the most disease-relevant neurological phenotypes are recapitulated in the conditionalParvalbumin knockout (PV-KO) model (Piguet et al., 2018). In this model, early neuropathyleads to a progressive decline in motor movement and increased sporadic and uncontrolledmovement. Vectors packaged in AAV-PHP.eB capsids were administered systemically to PV-KOmice via intravenous (IV) injection at postnatal day P35 at a dose level of 2.0 × 1012 vg / kg (‘lowdose’), 2.0 × 1013 vg / kg (‘medium dose’) or 5.0 × 1013 vg / kg (‘high dose’). Vehicle-treated WTand PV-KO control groups were also included in the study with each treatment group containing15 animals (Table 6). The study design is described in Fig. 27.Throughout the study, mice were weighed and assessed for a Jax-derived ‘Neuroscore’ weekly. Differences in body weight were observed between the vehicle-treated WT and PV-KO groups, and this difference was partially rescued in the medium and high-dose AAV-PHP.eB-NG347 treatment groups (data not shown). Neuroscore is a Jax-established measure of motor andneurological performance assessed by cage-side observations. Neuroscore increased over time inall PV-KO mice, starting as early as 8 weeks of age (Fig. 28). Significant differences wereobserved between the WT and PV-KO vehicle groups, and Neuroscore was partially rescued in the medium and high-dose AAV-PHP.eB-NG347 treatment groups (Fig. 28). Mice were also assayed for rotarod performance at 4 weeks, to establish baseline performance before dosing, and again at 9, 12, and 18 weeks of age. The time taken for each mouse to fall from the rotarod apparatus (longitudinal latency) was measured, and the reporteddata is an average of the last three trials performed on each given day (Fig. 29A-B). Rotarodperformance significantly decreased over time in vehicle-treated PV-KO mice, in contrast to WTmice. Motor performance on rotarod was partially rescued in a dose-dependent manner in themedium and high-dose AAV-PHP.eB-NG347 treatment groups (Fig. 29A-B). Tissues were collected from all animals at the study endpoint of 19 weeks of age (14 weeks post-dosing), and tissues from 6 animals in each treatment group were analyzed by biochemical evaluation. Vector genomes and transgenic human frataxin were detected in targettissues in a dose-dependent manner. Highest vector biodistribution was observed in the cortex,followed by cerebellum and liver (Fig. 30). Vector biodistribution in the quadriceps exhibited thehighest variability and was undetectable in the low-dose group. Expression of endogenous mousefrataxin, quantified by ELISA, was lower in PV-KO animals than in WT animals in each tissuetested (Fig. 31). Expression of transgenic human frataxin was highest in the cortex andcerebellum, with a trend towards dose-dependent increases in frataxin expression in these tissues. In the liver there is evidence that transgenic frataxin is regulated at the higher doses. Overall, this study shows that medium and high doses of AAV-PHP.eB-NG347 were efficacious in the PV-KO mouse model of FA, improving body weight and partially but significantly ameliorating motor phenotypes as measured by Neuroscore and rotarod. At thesedoses, AAV-PHP.eB-NG347 was well-tolerated in PV-KO mice and the medium dose was welltolerated in WT mice, with no overt toxicities observed. Importantly for FA, a dosage-sensitivecondition, AAV-PHP.eB-NG347-derived frataxin expression in the CNS was constrained todemonstrate that NG347 has the potential to achieve efficacy in FA without expressing toxic levels of protein.Table 6. Treatment groups for the efficacy of AAV-PHP.eB hFXN in PV-KO miceTreatment Genotype Vector Dose (vg / kg) n per groupgroup 1WT Vehicle - 152 PV-KO Vehicle - 153 PV-KO AAV-PHP.eB-NG347 2.0 x 1012 154 PV-KO AAV-PHP.eB-NG347 2.0 x 1013 155 PV-KO AAV-PHP.eB-NG347 5.0 x 1013 15SEQUENCE LISTING AND FEATURESSEQ ID NO / Construct description SEQ ID NO: 1 Wild-type human FXN coding sequenceSEQ ID NO: 2 Wild-type human FXN amino acid sequenceSEQ ID NO: 3 hFXN_in1 sequenceSEQ ID NO: 4 NG346; CBM-hFXN_in1-WPRE3-SV40pASEQ ID NO: 5 NG347; CBM-EXACT1-hFXN_in1-WPRE3-SV40pASEQ ID NO: 6 NG348; CBM-EXACT1-hFXN-WPRE3-SV40pASEQ ID NO: 7 CMV / CBA promoterSEQ ID NO: 8 MINX intronSEQ ID NO: 9 WPRE3SEQ ID NO:10 SV40pASEQ ID NO:11 NG349; hFXNP882-hFXN_in1-hFXNpA1SEQ ID NO:12 NG350; hFXNP882-EXACT1-hFXN_in1-hFXNpA1SEQ ID NO:13 hFXNP882 promoterSEQ ID NO:14 hFXN 5’UTRSEQ ID NO:15 hFXN enhancerSEQ ID NO:16 hFXNpA13’UTRSEQ ID NO: 1: Wild-type human FXN coding sequence ATGTGGACTCTCGGGCGCCGCGCAGTAGCCGGCCTCCTGGCGTCACCCAGCCCAGCC CAGGCCCAGACCCTCACCCGGGTCCCGCGGCCGGCAGAGTTGGCCCCACTCTGCGG CCGCCGTGGCCTGCGCACCGACATCGATGCGACCTGCACGCCCCGCCGCGCAAGTTC GAACCAACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGAT GAATTTGAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTA TGAAAGACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGC AGACAAGCCATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAAC TGTCAAACTGGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACA AGCAAATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGA AAAACTGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAG CTCACTAAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAA GATGCTTGA SEQ ID NO: 2: Wild-type human FXN amino acid sequence MWTLGRRAVAGLLASPSPAQAQTLTRVPRPAELAPLCGRRGLRTDIDATCTPRRASSNQ RGLNQIWNVKKQSVYLMNLRKSGTLGHPGSLDETTYERLAEETLDSLAEFFEDLADKPY TFEDYDVSFGSGVLTVKLGGDLGTYVINKQTPNKQIWLSSPSSGPKRYDWTGKNWVYS HDGVSLHELLAAELTKALKTKLDLSSLAYSGKDA* SEQ ID NO: 3: hFXN_in1 sequence ATGTGGACTCTCGGGCGCCGCGCAGTAGCCGGCCTCCTGGCGTCACCCAGCCCAGCC CAGGCCCAGACCCTCACCCGGGTCCCGCGGCCGGCAGAGTTGGCCCCACTCTGCGG CCGCCGTGGCCTGCGCACCGACATCGATGCGACCTGCACGCCCCGCCGCGCAGTAA GTATCCGCGCCGGGAACAGCCGCGGGCCGCACGCCGCGGGCCGCACGCCGCACGCC TGCGCAGGGAGGCGCCGCGCACGCCGGGGTCGCTCCGGGTACGCGCGCTGGACTAG CTCACCCCGCTCCTTCTCAGGGCGGCCCGGCGGAAGCGGCCTTGCAACTCCCTTCTC TGGTTCTCCCGGTTGCATTTACACTGGCTTCTGCTTTCCGAAGGAAAAGGGGACATT TTGTCCTGCGGTGCGACTGCGGGTCAAGGCACGGGCGAAGGCAGGGCAGGCTGGTG GAGGGGACCGATTCCGAGGGGTGTGCGGCTGTCTCCATGCTTGTCACTTCTCTGCGA TAACTTGTTTCAGTAATATTAATAGATGGTATCTGCTAGTATATACATACACATAAT GTGTGTGTCTGTGTGTATCTGTATATAGCGTGTGTGTTGTGTGTGTGTGTTTGCGCGC ACGGGCGCGCGCACACCTAATATTTTCAAGGCTGGATTTTTTTGAACGAAATGCTTT CCTGGAACGAGGTGAAACTTTCAGAGCTGCAGAATAGCTAGAGCAGCAGGGGCCCT GGCTTTTGGAAACTGACCCGACCTTTATTCCAGATTCTGCCCCACTCCGCAGAGCTG TGTGACCTTGGGGGATTCCCCTAACCTCTCTGAGACGTGGCTTTGTTTTCTGTAGGGA GAAGATAAAGGTGACGCCCATTTTGCGGACCTGGTGTGAGGATTAAATGGGAATAA CATAGATAAAGTCTTCAGAACTTCAAATTAGTTCCCCTTTCTTCCTTTGGGGGGTACA AAGAAATATCTGACCCAGTTACGCCACGGCTTGAAAGGAGGAAACCCAAAGAATGG CTGTGGGGATGAGGAAGATTCCTCAAGGGGAGGACATGGTATTTAATGAGGGTCTT GAAGATGCCAAGGAAGTGGTAGAGGGTGTTTCACGAGGAGGGAACCGTCTGGGCAA AGGCCAGGAAGGCGGAAGGTGATCCCTTCAGAGTGGCTGGTACGCCGCATGTATTA GGGGAGATGAAAGAGGCAGGCCACGTCCAAGCCATATTTGTGTTGCTCTCCGGAGT TTGTACTTTAGGCTTGAACTTCCCACACGTGTTATTTGGCCCACATTGTGTTTGAAGA AACTTTGGGATTGGTTGCCAGTGCTTAAAAGTTAGGACTTAGAAAATGGATTTCCTG GCAGGACGCGGTGGCTCATGCCCATAATCTCAGCACTTTGGGAGGCCTAGGAAGGT GGATCACCTGAGGTCCGGAGTTCAAGACTAACCTGGCCAACATGGTGAAACCCAGT ATCTACTAGCACTCGAATGTAGAAGTAGCAATATATAAATTATGCATTAATGGGTTA TAATTCACTGAAAAATAGTAACGTACTTCTTAACTTTGGCTTTCAGAGTTCGAACCA ACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGATGAATTT GAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTATGAAA GACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGCAGACA AGCCATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAACTGTCA AACTGGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACAAGCAA ATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGAAAAAC TGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAGCTCACT AAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAAGATGCT TGA SEQ ID NO: 4: NG346; CBM-hFXN_in1-WPRE3-SV40pA CCTGCAGGCAGCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGG CGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGG AGTGGCCAACTCCATCACTAGGGGTTCCTGCGGCCGCACGCGTACTAGTTATTAATA GTAATCAATTACGGGGTCATTAGTTCATAGCCCATATATGGAGTTCCGCGTTACATA ACTTACGGTAAATGGCCCGCCTGGCTGACCGCCCAACGACCCCCGCCCATTGACGTC AATAATGACGTATGTTCCCATAGTAACGCCAATAGGGACTTTCCATTGACGTCAATG GGTGGAGTATTTACGGTAAACTGCCCACTTGGCAGTACATCAAGTGTATCATATGCC AAGTACGCCCCCTATTGACGTCAATGACGGTAAATGGCCCGCCTGGCATTATGCCCA GTACATGACCTTATGGGACTTTCCTACTTGGCAGTACATCTACGTATTAGTCATCGCT ATTACCATGGTCGAGGTGAGCCCCACGTTCTGCTTCACTCTCCCCATCTCCCCCCCCT CCCCACCCCCAATTTTGTATTTATTTATTTTTTAATTATTTTGTGCAGCGATGGGGGC GGGGGGGGGGGGGGGGCGCGCGCCAGGCGGGGCGGGGCGGGGCGAGGGGCGGGG CGGGGCGAGGCGGAGAGGTGCGGCGGCAGCCAATCAGAGCGGCGCGCTCCGAAAG TTTCCTTTTATGGCGAGGCGGCGGCGGCGGCGGCCCTATAAAAAGCGAAGCGCGCG GCGGGCGGATTCTTCTGACACAACAGTCTCGAACTTAAGCTGCAGAAGTTGGTCGTG AGGCACTGGGCAGGTGTCCACTCCCAGTTCAATTACAGCTCTTAAGGCTAGAGTACT CGGAAACCCGTCGGCCTCCGAACGGTAAGAGCCTAGCATGTAGAACTGGTTACCTG CAGCCCAAGCTTGCTGCACGTCTAGGGCTCACCGGGTTTCCTTGATGAGGTACCGAC ATACTTATCCTGTCCCTTTTTTTTCCACAGCTCGCGGTTGAGGACAAACTCTTCACCG GTCGCCACCATGTGGACTCTCGGGCGCCGCGCAGTAGCCGGCCTCCTGGCGTCACCC AGCCCAGCCCAGGCCCAGACCCTCACCCGGGTCCCGCGGCCGGCAGAGTTGGCCCC ACTCTGCGGCCGCCGTGGCCTGCGCACCGACATCGATGCGACCTGCACGCCCCGCCG CGCAGTAAGTATCCGCGCCGGGAACAGCCGCGGGCCGCACGCCGCGGGCCGCACGC CGCACGCCTGCGCAGGGAGGCGCCGCGCACGCCGGGGTCGCTCCGGGTACGCGCGC TGGACTAGCTCACCCCGCTCCTTCTCAGGGCGGCCCGGCGGAAGCGGCCTTGCAACT CCCTTCTCTGGTTCTCCCGGTTGCATTTACACTGGCTTCTGCTTTCCGAAGGAAAAGG GGACATTTTGTCCTGCGGTGCGACTGCGGGTCAAGGCACGGGCGAAGGCAGGGCAG GCTGGTGGAGGGGACCGATTCCGAGGGGTGTGCGGCTGTCTCCATGCTTGTCACTTC TCTGCGATAACTTGTTTCAGTAATATTAATAGATGGTATCTGCTAGTATATACATACA CATAATGTGTGTGTCTGTGTGTATCTGTATATAGCGTGTGTGTTGTGTGTGTGTGTTT GCGCGCACGGGCGCGCGCACACCTAATATTTTCAAGGCTGGATTTTTTTGAACGAAA TGCTTTCCTGGAACGAGGTGAAACTTTCAGAGCTGCAGAATAGCTAGAGCAGCAGG GGCCCTGGCTTTTGGAAACTGACCCGACCTTTATTCCAGATTCTGCCCCACTCCGCA GAGCTGTGTGACCTTGGGGGATTCCCCTAACCTCTCTGAGACGTGGCTTTGTTTTCTG TAGGGAGAAGATAAAGGTGACGCCCATTTTGCGGACCTGGTGTGAGGATTAAATGG GAATAACATAGATAAAGTCTTCAGAACTTCAAATTAGTTCCCCTTTCTTCCTTTGGGG GGTACAAAGAAATATCTGACCCAGTTACGCCACGGCTTGAAAGGAGGAAACCCAAA GAATGGCTGTGGGGATGAGGAAGATTCCTCAAGGGGAGGACATGGTATTTAATGAG GGTCTTGAAGATGCCAAGGAAGTGGTAGAGGGTGTTTCACGAGGAGGGAACCGTCT GGGCAAAGGCCAGGAAGGCGGAAGGTGATCCCTTCAGAGTGGCTGGTACGCCGCAT GTATTAGGGGAGATGAAAGAGGCAGGCCACGTCCAAGCCATATTTGTGTTGCTCTCC GGAGTTTGTACTTTAGGCTTGAACTTCCCACACGTGTTATTTGGCCCACATTGTGTTT GAAGAAACTTTGGGATTGGTTGCCAGTGCTTAAAAGTTAGGACTTAGAAAATGGATT TCCTGGCAGGACGCGGTGGCTCATGCCCATAATCTCAGCACTTTGGGAGGCCTAGGA AGGTGGATCACCTGAGGTCCGGAGTTCAAGACTAACCTGGCCAACATGGTGAAACC CAGTATCTACTAGCACTCGAATGTAGAAGTAGCAATATATAAATTATGCATTAATGG GTTATAATTCACTGAAAAATAGTAACGTACTTCTTAACTTTGGCTTTCAGAGTTCGA ACCAACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGATGA ATTTGAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTATG AAAGACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGCA GACAAGCCATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAACT GTCAAACTGGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACAA GCAAATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGAA AAACTGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAGCT CACTAAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAAGA TGCTTGAGGATCCTAATGCTGGTAGCTAGCATAATCAACCTCTGGATTACAAAATTT GTGAAAGATTGACTGGTATTCTTAACTATGTTGCTCCTTTTACGCTATGTGGATACGC TGCTTTAATGCCTTTGTATCATGCTATTGCTTCCCGTATGGCTTTCATTTTCTCCTCCT TGTATAAATCCTGGTTAGTTCTTGCCACGGCGGAACTCATCGCCGCCTGCCTTGCCC GCTGCTGGACAGGGGCTCGGCTGTTGGGCACTGACAATTCCGTGGTGAGCTCACTTG TTTATTGCAGCTTATAATGGTTACAAATAAAGCAATAGCATCACAAATTTCACAAAT AAAGCATTTTTTTCACTGCATTCTAGTTGTGGTTTGTCCAAACTCATCAATGTATCTT ATCATGTCTGTTCCGGACACGTGCGGACCGAGCGGCCGCAGGAACCCCTAGTGATG GAGTTGGCCACTCCCTCTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGCGACCAAAG GTCGCCCGACGCCCGGGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGAGCGCGCAG CTGCCTGCAGG SEQ ID NO: 5: NG347; CBM-EXACT1-hFXN_in1-WPRE3-SV40pA CCTGCAGGCAGCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGG CGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGG AGTGGCCAACTCCATCACTAGGGGTTCCTGCGGCCGCACGCGTACTAGTTATTAATA GTAATCAATTACGGGGTCATTAGTTCATAGCCCATATATGGAGTTCCGCGTTACATA ACTTACGGTAAATGGCCCGCCTGGCTGACCGCCCAACGACCCCCGCCCATTGACGTC AATAATGACGTATGTTCCCATAGTAACGCCAATAGGGACTTTCCATTGACGTCAATG GGTGGAGTATTTACGGTAAACTGCCCACTTGGCAGTACATCAAGTGTATCATATGCC AAGTACGCCCCCTATTGACGTCAATGACGGTAAATGGCCCGCCTGGCATTATGCCCA GTACATGACCTTATGGGACTTTCCTACTTGGCAGTACATCTACGTATTAGTCATCGCT ATTACCATGGTCGAGGTGAGCCCCACGTTCTGCTTCACTCTCCCCATCTCCCCCCCCT CCCCACCCCCAATTTTGTATTTATTTATTTTTTAATTATTTTGTGCAGCGATGGGGGC GGGGGGGGGGGGGGGGCGCGCGCCAGGCGGGGCGGGGCGGGGCGAGGGGCGGGG CGGGGCGAGGCGGAGAGGTGCGGCGGCAGCCAATCAGAGCGGCGCGCTCCGAAAG TTTCCTTTTATGGCGAGGCGGCGGCGGCGGCGGCCCTATAAAAAGCGAAGCGCGCG GCGGGCGGATTCTTCTGACACAACAGTCTCGAACTTAAGCTGCAGAAGTTGGTCGTG AGGCACTGGGCAGGTGTCCACTCCCAGTTCAATTACAGCTCTTAAGGCTAGAGTACT CGGAAACCCGTCGGCCTCCGAACGGTAAGAGCCTAGCATGTAGAACTGGTTACCTG CAGCCCAAGCTTGCTGCACGTCTAGGGCGGACTGTTTGAATGAGGCTTCAGTACTTT ACAGAATCGTTGCCTGCACATCTTGGAAACACTTGCTGGGATTACTTCGACTTCTTA ACCCAACAGAAGGCTCGAGAAGGTATATTGCTGTTGACAGTGAGCGAAACGATATG GGCTGAATACAATAGTGAAGCCACAGATGTATTGTATTCAGCCCATATCGTTGTGCC TACTGCCTCGGACTTCAAGGGGCTAGAATTCGAGCAATTATCTTGTTTACTAAAACT GAATACCTTGCTATCTCTTTGATACATTTTTACAAAGCTGAATTAAAATGGTATAAAT TAAATCACTTTCAGCTCACCGGGTTTCCTTGATGAGGTACCGACATACTTATCCTGTC CCTTTTTTTTCCACAGCTCGCGGTTGAGGACAAACTCTTCACCGGTCGCCACCATGTG GACTCTCGGGCGCCGCGCAGTAGCCGGCCTCCTGGCGTCACCCAGCCCAGCCCAGG CCCAGACCCTCACCCGGGTCCCGCGGCCGGCAGAGTTGGCCCCACTCTGCGGCCGCC GTGGCCTGCGCACCGACATCGATGCGACCTGCACGCCCCGCCGCGCAGTAAGTATC CGCGCCGGGAACAGCCGCGGGCCGCACGCCGCGGGCCGCACGCCGCACGCCTGCGC AGGGAGGCGCCGCGCACGCCGGGGTCGCTCCGGGTACGCGCGCTGGACTAGCTCAC CCCGCTCCTTCTCAGGGCGGCCCGGCGGAAGCGGCCTTGCAACTCCCTTCTCTGGTT CTCCCGGTTGCATTTACACTGGCTTCTGCTTTCCGAAGGAAAAGGGGACATTTTGTC CTGCGGTGCGACTGCGGGTCAAGGCACGGGCGAAGGCAGGGCAGGCTGGTGGAGG GGACCGATTCCGAGGGGTGTGCGGCTGTCTCCATGCTTGTCACTTCTCTGCGATAAC TTGTTTCAGTAATATTAATAGATGGTATCTGCTAGTATATACATACACATAATGTGTG TGTCTGTGTGTATCTGTATATAGCGTGTGTGTTGTGTGTGTGTGTTTGCGCGCACGGG CGCGCGCACACCTAATATTTTCAAGGCTGGATTTTTTTGAACGAAATGCTTTCCTGG AACGAGGTGAAACTTTCAGAGCTGCAGAATAGCTAGAGCAGCAGGGGCCCTGGCTT TTGGAAACTGACCCGACCTTTATTCCAGATTCTGCCCCACTCCGCAGAGCTGTGTGA CCTTGGGGGATTCCCCTAACCTCTCTGAGACGTGGCTTTGTTTTCTGTAGGGAGAAG ATAAAGGTGACGCCCATTTTGCGGACCTGGTGTGAGGATTAAATGGGAATAACATA GATAAAGTCTTCAGAACTTCAAATTAGTTCCCCTTTCTTCCTTTGGGGGGTACAAAG AAATATCTGACCCAGTTACGCCACGGCTTGAAAGGAGGAAACCCAAAGAATGGCTG TGGGGATGAGGAAGATTCCTCAAGGGGAGGACATGGTATTTAATGAGGGTCTTGAA GATGCCAAGGAAGTGGTAGAGGGTGTTTCACGAGGAGGGAACCGTCTGGGCAAAGG CCAGGAAGGCGGAAGGTGATCCCTTCAGAGTGGCTGGTACGCCGCATGTATTAGGG GAGATGAAAGAGGCAGGCCACGTCCAAGCCATATTTGTGTTGCTCTCCGGAGTTTGT ACTTTAGGCTTGAACTTCCCACACGTGTTATTTGGCCCACATTGTGTTTGAAGAAACT TTGGGATTGGTTGCCAGTGCTTAAAAGTTAGGACTTAGAAAATGGATTTCCTGGCAG GACGCGGTGGCTCATGCCCATAATCTCAGCACTTTGGGAGGCCTAGGAAGGTGGAT CACCTGAGGTCCGGAGTTCAAGACTAACCTGGCCAACATGGTGAAACCCAGTATCT ACTAGCACTCGAATGTAGAAGTAGCAATATATAAATTATGCATTAATGGGTTATAAT TCACTGAAAAATAGTAACGTACTTCTTAACTTTGGCTTTCAGAGTTCGAACCAACGT GGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGATGAATTTGAGG AAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTATGAAAGACTA GCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGCAGACAAGCC ATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAACTGTCAAACT GGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACAAGCAAATCT GGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGAAAAACTGGG TGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAGCTCACTAAAG CCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAAGATGCTTGAG GATCCTAATGCTGCTATGAAACGATATGGGCTGAATACAAATCACAGGCTATGAAA CGATATGGGCTGAATACAAATCACAGGCTATGAAACGATATGGGCTGAATACAAAT CACAGGGTAGCTAGCATAATCAACCTCTGGATTACAAAATTTGTGAAAGATTGACTG GTATTCTTAACTATGTTGCTCCTTTTACGCTATGTGGATACGCTGCTTTAATGCCTTT GTATCATGCTATTGCTTCCCGTATGGCTTTCATTTTCTCCTCCTTGTATAAATCCTGGT TAGTTCTTGCCACGGCGGAACTCATCGCCGCCTGCCTTGCCCGCTGCTGGACAGGGG CTCGGCTGTTGGGCACTGACAATTCCGTGGTGAGCTCACTTGTTTATTGCAGCTTATA ATGGTTACAAATAAAGCAATAGCATCACAAATTTCACAAATAAAGCATTTTTTTCAC TGCATTCTAGTTGTGGTTTGTCCAAACTCATCAATGTATCTTATCATGTCTGTTCCGG ACACGTGCGGACCGAGCGGCCGCAGGAACCCCTAGTGATGGAGTTGGCCACTCCCT CTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGCGACCAAAGGTCGCCCGACGCCCG GGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGAGCGCGCAGCTGCCTGCAGG SEQ ID NO: 6: NG348; CBM-EXACT1-hFXN-WPRE3-SV40pA CCTGCAGGCAGCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGG CGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGG AGTGGCCAACTCCATCACTAGGGGTTCCTGCGGCCGCACGCGTACTAGTTATTAATA GTAATCAATTACGGGGTCATTAGTTCATAGCCCATATATGGAGTTCCGCGTTACATA ACTTACGGTAAATGGCCCGCCTGGCTGACCGCCCAACGACCCCCGCCCATTGACGTC AATAATGACGTATGTTCCCATAGTAACGCCAATAGGGACTTTCCATTGACGTCAATG GGTGGAGTATTTACGGTAAACTGCCCACTTGGCAGTACATCAAGTGTATCATATGCC AAGTACGCCCCCTATTGACGTCAATGACGGTAAATGGCCCGCCTGGCATTATGCCCA GTACATGACCTTATGGGACTTTCCTACTTGGCAGTACATCTACGTATTAGTCATCGCT ATTACCATGGTCGAGGTGAGCCCCACGTTCTGCTTCACTCTCCCCATCTCCCCCCCCT CCCCACCCCCAATTTTGTATTTATTTATTTTTTAATTATTTTGTGCAGCGATGGGGGC GGGGGGGGGGGGGGGGCGCGCGCCAGGCGGGGCGGGGCGGGGCGAGGGGCGGGG CGGGGCGAGGCGGAGAGGTGCGGCGGCAGCCAATCAGAGCGGCGCGCTCCGAAAG TTTCCTTTTATGGCGAGGCGGCGGCGGCGGCGGCCCTATAAAAAGCGAAGCGCGCG GCGGGCGGATTCTTCTGACACAACAGTCTCGAACTTAAGCTGCAGAAGTTGGTCGTG AGGCACTGGGCAGGTGTCCACTCCCAGTTCAATTACAGCTCTTAAGGCTAGAGTACT CGGAAACCCGTCGGCCTCCGAACGGTAAGAGCCTAGCATGTAGAACTGGTTACCTG CAGCCCAAGCTTGCTGCACGTCTAGGGCGGACTGTTTGAATGAGGCTTCAGTACTTT ACAGAATCGTTGCCTGCACATCTTGGAAACACTTGCTGGGATTACTTCGACTTCTTA ACCCAACAGAAGGCTCGAGAAGGTATATTGCTGTTGACAGTGAGCGAAACGATATG GGCTGAATACAATAGTGAAGCCACAGATGTATTGTATTCAGCCCATATCGTTGTGCC TACTGCCTCGGACTTCAAGGGGCTAGAATTCGAGCAATTATCTTGTTTACTAAAACT GAATACCTTGCTATCTCTTTGATACATTTTTACAAAGCTGAATTAAAATGGTATAAAT TAAATCACTTTCAGCTCACCGGGTTTCCTTGATGAGGTACCGACATACTTATCCTGTC CCTTTTTTTTCCACAGCTCGCGGTTGAGGACAAACTCTTCACCGGTCGCCACCATGTG GACTCTCGGGCGCCGCGCAGTAGCCGGCCTCCTGGCGTCACCCAGCCCAGCCCAGG CCCAGACCCTCACCCGGGTCCCGCGGCCGGCAGAGTTGGCCCCACTCTGCGGCCGCC GTGGCCTGCGCACCGACATCGATGCGACCTGCACGCCCCGCCGCGCAAGTTCGAAC CAACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGATGAAT TTGAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTATGAA AGACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGCAGAC AAGCCATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAACTGTC AAACTGGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACAAGCA AATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGAAAAA CTGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAGCTCAC TAAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAAGATGC TTGAGGATCCTAATGCTGCTATGAAACGATATGGGCTGAATACAAATCACAGGCTAT GAAACGATATGGGCTGAATACAAATCACAGGCTATGAAACGATATGGGCTGAATAC AAATCACAGGGTAGCTAGCATAATCAACCTCTGGATTACAAAATTTGTGAAAGATTG ACTGGTATTCTTAACTATGTTGCTCCTTTTACGCTATGTGGATACGCTGCTTTAATGC CTTTGTATCATGCTATTGCTTCCCGTATGGCTTTCATTTTCTCCTCCTTGTATAAATCC TGGTTAGTTCTTGCCACGGCGGAACTCATCGCCGCCTGCCTTGCCCGCTGCTGGACA GGGGCTCGGCTGTTGGGCACTGACAATTCCGTGGTGAGCTCACTTGTTTATTGCAGC TTATAATGGTTACAAATAAAGCAATAGCATCACAAATTTCACAAATAAAGCATTTTT TTCACTGCATTCTAGTTGTGGTTTGTCCAAACTCATCAATGTATCTTATCATGTCTGT TCCGGACACGTGCGGACCGAGCGGCCGCAGGAACCCCTAGTGATGGAGTTGGCCAC TCCCTCTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGCGACCAAAGGTCGCCCGACG CCCGGGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGAGCGCGCAGCTGCCTGCAGG SEQ ID NO: 7: CMV / CBA promoter CTAGTTATTAATAGTAATCAATTACGGGGTCATTAGTTCATAGCCCATATATGGA GTTCCGCGTTACATAACTTACGGTAAATGGCCCGCCTGGCTGACCGCCCAACGACCC CCGCCCATTGACGTCAATAATGACGTATGTTCCCATAGTAACGCCAATAGGGACTTT CCATTGACGTCAATGGGTGGAGTATTTACGGTAAACTGCCCACTTGGCAGTACATCA AGTGTATCATATGCCAAGTACGCCCCCTATTGACGTCAATGACGGTAAATGGCCCGC CTGGCATTATGCCCAGTACATGACCTTATGGGACTTTCCTACTTGGCAGTACATCTAC GTATTAGTCATCGCTATTACCATGGTCGAGGTGAGCCCCACGTTCTGCTTCACTCTCC CCATCTCCCCCCCCTCCCCACCCCCAATTTTGTATTTATTTATTTTTTAATTATTTTGT GCAGCGATGGGGGCGGGGGGGGGGGGGGGGCGCGCGCCAGGCGGGGCGGGGCGG GGCGAGGGGCGGGGCGGGGCGAGGCGGAGAGGTGCGGCGGCAGCCAATCAGAGCG GCGCGCTCCGAAAGTTTCCTTTTATGGCGAGGCGGCGGCGGCGGCGGCCCTATAAA AAGCGAAGCGCGCGGCGGGCG SEQ ID NO: 8: MINX intron CGGAAACCCGTCGGCCTCCGAACGGTAAGAGCCTAGCATGTAGAACTGGTTACCTG CAGCCCAAGCTTGCTGCACGTCTAGGGCTCACCGGGTTTCCTTGATGAGGTACCGAC ATACTTATCCTGTCCCTTTTTTTTCCACAGCTCGCGGTTGAGGACAAACTCTTC SEQ ID NO: 9: WPRE3 ATAATCAACCTCTGGATTACAAAATTTGTGAAAGATTGACTGGTATTCTTAACTATG TTGCTCCTTTTACGCTATGTGGATACGCTGCTTTAATGCCTTTGTATCATGCTATTGCT TCCCGTATGGCTTTCATTTTCTCCTCCTTGTATAAATCCTGGTTAGTTCTTGCCACGGC GGAACTCATCGCCGCCTGCCTTGCCCGCTGCTGGACAGGGGCTCGGCTGTTGGGCAC TGACAATTCCGTGGT SEQ ID NO:10: SV40pA ACTTGTTTATTGCAGCTTATAATGGTTACAAATAAAGCAATAGCATCACAAATTTCA CAAATAAAGCATTTTTTTCACTGCATTCTAGTTGTGGTTTGTCCAAACTCATCAATGT ATCTTATCATGTCTGT SEQ ID NO:11: NG349; hFXNP882-hFXN_in1-hFXNpA1 CCTGCAGGCAGCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGG CGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGG AGTGGCCAACTCCATCACTAGGGGTTCCTGCGGCCGCACGCGTAATTCAAAGTTAGA CCAGAATAGTGGTTCTCAACCAGGGGCAATTTTACTCCTTAGGGGACCTTTTCACAA TGTCTGGAGACATTTTTGATTGTCACTATTGAATGGGAGAGCAGATACTACTGCCAT CTAGTGGGTGGAGACCAAGAATGCTGCTAAACCACCTTACAATGCATGGGACAACC ACCACGACAGAGTTAGCCATGTGTTGCTTAACAACAGGGATACATTCTGGGAAATG CATCATTAGGTCAGGACCACACCACTGCACTCCAGCCTGGGCAACAGAGTGAGACT CTGTCTCAAACAAACAAATAAATGAGGCGGGTGGATCACGAGGTCAGTAGATCGAG ACCATCCTGGCTAACACGGTGAAACCCGTCTCTACTAAAAAAAAAAAAAAATACAA AAAATTAGCCAGGCATGGTGGCGGGCGCCTGTAGTCCCAGTTACTCGGGAGGCTGA GGCAGGAGAATGGCGTGAAACCGGGAGGCAGAGCTTGCAGTGAGCCGAGATCGCA CCACTGCCCTCCAGCCTGGGCGACAGAGCGAGACTCCGTCTCAATCAATCAATCAAT CAATAAAATCTATTAACAATATTTATTGTGCACTTAACAGGAACATGCCCTGTCCAA AAAAAACTTTACAGGGCTTAACTCATTTTATCCTTACCACAATCCTATGAAGTAGGA ACTTTTATAAAACGCATTTTATAAACAAGGCACAGAGAGGTTAATTAACTTGCCCTC TGGTCACACAGCTAGGAAGTGGGCAGAGTACAGATTTACACAAGGCATCCGTCTCC TGGCCCCACATACCCAACTGCTGTAAACCCATACCGGCGGCCAAGCAGCCTCAATTT GTGCATGCACCCACTTCCCAGCAAGACAGCAGCTCCCAAGTTCCTCCTGTTTAGAAT TTTAGAAGCGGCGGGCCACCAGGCTGCAGTCTCCCTTGGGTCAGGGGTCCTGGTTGC ACTCCGTGCTTTGCACAAAGCAGGCTCTCCATTTTTGTTAAATGCACGAATAGTGCT AAGCTGGGAAGTTCTTCCTGAGGTCTAACCTCTAGCTGCTCCCCCACAGAAGAGTGC CTGCGGCCAGTGGCCACCAGGGGTCGCCGCAGCACCCAGCGCTGGAGGGCGGAGCG GGCGGCAGACCCGGAGCAGCATGTGGACTCTCGGGCGCCGCGCAGTAGCCGGCCTC CTGGCGTCACCCAGCCCAGCCCAGGCCCAGACCCTCACCCGGGTCCCGCGGCCGGC AGAGTTGGCCCCACTCTGCGGCCGCCGTGGCCTGCGCACCGACATCGATGCGACCTG CACGCCCCGCCGCGCAGTAAGTATCCGCGCCGGGAACAGCCGCGGGCCGCACGCCG CGGGCCGCACGCCGCACGCCTGCGCAGGGAGGCGCCGCGCACGCCGGGGTCGCTCC GGGTACGCGCGCTGGACTAGCTCACCCCGCTCCTTCTCAGGGCGGCCCGGCGGAAG CGGCCTTGCAACTCCCTTCTCTGGTTCTCCCGGTTGCATTTACACTGGCTTCTGCTTTC CGAAGGAAAAGGGGACATTTTGTCCTGCGGTGCGACTGCGGGTCAAGGCACGGGCG AAGGCAGGGCAGGCTGGTGGAGGGGACCGGTTCCGAGGGGTGTGCGGCTGTCTCCA TGCTTGTCACTTCTCTGCGATAACTTGTTTCAGTAATATTAATAGATGGTATCTGCTA GTATATACATACACATAATGTGTGTGTCTGTGTGTATCTGTATATAGCGTGTGTGTTG TGTGTGTGTGTTTGCGCGCACGGGCGCGCGCACACCTAATATTTTCAAGGCTGGATT TTTTTGAACGAAATGCTTTCCTGGAACGAGGTGAAACTTTCAGAGCTGCAGAATAGC TAGAGCAGCAGGGGCCCTGGCTTTTGGAAACTGACCCGACCTTTATTCCAGATTCTG CCCCACTCCGCAGAGCTGTGTGACCTTGGGGGATTCCCCTAACCTCTCTGAGACGTG GCTTTGTTTTCTGTAGGGAGAAGATAAAGGTGACGCCCATTTTGCGGACCTGGTGTG AGGATTAAATGGGAATAACATAGATAAAGTCTTCAGAACTTCAAATTAGTTCCCCTT TCTTCCTTTGGGGGGTACAAAGAAATATCTGACCCAGTTACGCCACGGCTTGAAAGG AGGAAACCCAAAGAATGGCTGTGGGGATGAGGAAGATTCCTCAAGGGGAGGACAT GGTATTTAATGAGGGTCTTGAAGATGCCAAGGAAGTGGTAGAGGGTGTTTCACGAG GAGGGAACCGTCTGGGCAAAGGCCAGGAAGGCGGAAGGGGATCCCTTCAGAGTGG CTGGTACGCCGCATGTATTAGGGGAGATGAAAGAGGCAGGCCACGTCCAAGCCATA TTTGTGTTGCTCTCCGGAGTTTGTACTTTAGGCTTGAACTTCCCACACGTGTTATTTG GCCCACATTGTGTTTGAAGAAACTTTGGGATTGGTTGCCAGTGCTTAAAAGTTAGGA CTTAGAAAATGGATTTCCTGGCAGGACGCGGTGGCTCATGCCCATAATCTCAGCACT TTGGGAGGCCTAGGAAGGTGGATCACCTGAGGTCCGGAGTTCAAGACTAACCTGGC CAACATGGTGAAACCCAGTATCTACTAGCACTCGAATGTAGAAGTAGCAATATATA AATTATGCATTAATGGGTTATAATTCACTGAAAAATAGTAACGTACTTCTTAACTTT GGCTTTCAGAGTTCGAACCAACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCA GAGTGTCTATTTGATGAATTTGAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCT AGATGAGACCACCTATGAAAGACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGT TTTTTGAAGACCTTGCAGACAAGCCATACACGTTTGAGGACTATGATGTCTCCTTTG GGAGTGGTGTCTTAACTGTCAAACTGGGTGGAGATCTAGGAACCTATGTGATCAACA AGCAGACGCCAAACAAGCAAATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTT ATGACTGGACTGGGAAAAACTGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAG CTGCTGGCCGCAGAGCTCACTAAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTG GCCTATTCCGGAAAAGATGCTTGAGGATCCCCCAGTACATGACCTTATGGGCTAGCT GCAGGAGCTTTCTTATATCCACCTTCCTCCTTTTCTCTCAGCCCATCATCTAGCTACA CAGTCTCCAGGGTAAGCTTTCAGAAAGGCAATCTCTTGTCTGTAAAACCTAAGCAGG ACCAAGGCCAAGTTTCTTAGCCTGAAAAATGTGCTTTTCTGACTGAACTGTTCAGGC ACTGACTCTACATATAATTATGCTTTTCTACCCCCTCACACTCAACACTTTGACTCCA GCAATCCCAAATCCCCAGATCCCTAAGTGTGCTGTGCTATTTTCACGTGGCTCTCAG ACTTGGCCAGTGCTGTTTCCATTTTGGTCTTTATTCCCCACATCTCTGCCTGGGGGGT AGATTCTACCCTGAAAAATGTTCTTGGCACAGCCTTGCAAACTCCTCCTCCACTCAG CCTCTGCCTGGATGCCCTTGATTGTTCCATGTCCTCAGCATACCATGTTTGTCTTTCC CAGCACTGACCTACCATGTGTCACCCCTGCTTGGCTGTACCTTCCATGAGGCTAGGA CTATGTGTCTCCTTTGTTGACTGCTGTTGCCCTAGCATCTTGCACAGTTCCTTGCACA CAATTAGAGCTCTATAAATGTCAAATAAATGTGTTATAATTATATGTTTAAGATAGT TGTTCAAATAAACTCTAAATAACCCCAACTCCAAGAGTGTTAGCAAGAAATATAAAT TTTACAGAAGAATGGTTGGAGGTGGGTTGTGCGGACCGAGCGGCCGCAGGAACCCC TAGTGATGGAGTTGGCCACTCCCTCTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGC GACCAAAGGTCGCCCGACGCCCGGGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGA GCGCGCAGCTGCCTGCAGG SEQ ID NO:12: NG350; hFXNP882-EXACT1-hFXN_in1-hFXNpA1 CCTGCAGGCAGCTGCGCGCTCGCTCGCTCACTGAGGCCGCCCGGGCAAAGCCCGGG CGTCGGGCGACCTTTGGTCGCCCGGCCTCAGTGAGCGAGCGAGCGCGCAGAGAGGG AGTGGCCAACTCCATCACTAGGGGTTCCTGCGGCCGCACGCGTAATTCAAAGTTAGA CCAGAATAGTGGTTCTCAACCAGGGGCAATTTTACTCCTTAGGGGACCTTTTCACAA TGTCTGGAGACATTTTTGATTGTCACTATTGAATGGGAGAGCAGATACTACTGCCAT CTAGTGGGTGGAGACCAAGAATGCTGCTAAACCACCTTACAATGCATGGGACAACC ACCACGACAGAGTTAGCCATGTGTTGCTTAACAACAGGGATACATTCTGGGAAATG CATCATTAGGTCAGGACCACACCACTGCACTCCAGCCTGGGCAACAGAGTGAGACT CTGTCTCAAACAAACAAATAAATGAGGCGGGTGGATCACGAGGTCAGTAGATCGAG ACCATCCTGGCTAACACGGTGAAACCCGTCTCTACTAAAAAAAAAAAAAAATACAA AAAATTAGCCAGGCATGGTGGCGGGCGCCTGTAGTCCCAGTTACTCGGGAGGCTGA GGCAGGAGAATGGCGTGAAACCGGGAGGCAGAGCTTGCAGTGAGCCGAGATCGCA CCACTGCCCTCCAGCCTGGGCGACAGAGCGAGACTCCGTCTCAATCAATCAATCAAT CAATAAAATCTATTAACAATATTTATTGTGCACTTAACAGGAACATGCCCTGTCCAA AAAAAACTTTACAGGGCTTAACTCATTTTATCCTTACCACAATCCTATGAAGTAGGA ACTTTTATAAAACGCATTTTATAAACAAGGCACAGAGAGGTTAATTAACTTGCCCTC TGGTCACACAGCTAGGAAGTGGGCAGAGTACAGATTTACACAAGGCATCCGTCTCC TGGCCCCACATACCCAACTGCTGTAAACCCATACCGGCGGCCAAGCAGCCTCAATTT GTGCATGCACCCACTTCCCAGCAAGACAGCAGCTCCCAAGTTCCTCCTGTTTAGAAT TTTAGAAGCGGCGGGCCACCAGGCTGCAGTCTCCCTTGGGTCAGGGGTCCTGGTTGC ACTCCGTGCTTTGCACAAAGCAGGCTCTCCATTTTTGTTAAATGCACGAATAGTGCT AAGCTGGGAAGTTCTTCCTGAGGTCTAACCTCTAGCTGCTCCCCCACAGAAGAGTGC CTGCGGCCAGTGGCCACCAGGGGTCGCCGCAGCACCCAGCGCTGGAGGGCGGAGCG GGCGGCAGACCCGGAGCAGCATGTGGACTCTCGGGCGCCGCGCAGTAGCCGGCCTC CTGGCGTCACCCAGCCCAGCCCAGGCCCAGACCCTCACCCGGGTCCCGCGGCCGGC AGAGTTGGCCCCACTCTGCGGCCGCCGTGGCCTGCGCACCGACATCGATGCGACCTG CACGCCCCGCCGCGCAGTAAGTATCCGCGCCGGGAACAGCCGCGGGCCGCACGCCG CGGGCCGCACGCCGCACGCCTGCGCAGGGAGGCGCCGCGCACGCCGGGGTCGCTCC GGGTACGCGCGCTGGACTAGCTCACCCCGCTCCTTCTCAGGGCGGCCCGGCGGAAG CGGCCTTGCAACTCCCTTCTCTGGTTCTCCCGGTTGCATTTACACTGGCTTCTGCTTTC CGAAGGAAAAGGGGACATTTTGTCCTGCGGTGCGACTGCGGGTCAAGGCACGGGCG AAGGCAGGGCAGGCTGGTGGAGGGGACCGGTTCCGAGGGGTGTGCGGCTGTCTCCA TGCTTGTCACTTCTCTGCGATAACTTGTTTCAGTAATATTAATAGATGGTATCTGCTA GTATATACATACACATAATGTGTGTGTCTGTGTGTATCTGTATATAGCGTGTGTGTTG TGTGTGTGTGTTTGCGCGCACGGGCGCGCGCACACCTAATATTTTCAAGGCTGGATT TTTTTGAACGAAATGCTTTCCTGGAACGAGGTGAAACTTTCAGAGCTGCAGAATAGC TAGAGCAGCAGGGGCCCTGGCTTTTGGAAACTGACCCGACCTTTATTCCAGATTCTG CCCCACTCCGCAGAGCTGTGTGACCTTGGGGGATTCCCCTAACCTCTCTGAGACGTG GCTTTGTTTTCTGTAGGGAGAAGATAAAGGTGACGCCCATTTTGCGGACCTGGTGTG AGGATTAAATGGGAATAACATAGATAAAGTCTTCAGAACTTCAAATTAGTTCCCCTT TCTTCCTTTGGGGGGTACAAAGAAATATCTGACCCAGTTACGCCACGGCTTGAAAGG AGGAAACCCAAAGAATGGCTGTGGGGATGAGGAAGATTCCTCAAGGGGAGGACAT GGTATTTAATGAGGGTCTTGAAGATGCCAAGGAAGTGGTAGAGGGTGTTTCACGAG GAGGGAACCGTCTGGGCAAAGGCCAGGAAGGCGGAAGGGGATCCCTTCAGAGTGG CTGGTACGCCGCATGTATTAGGGGAGATGAAAGAGGCAGGCCACGTCCAAGCCATA TTTGTGTTGCTCTCCGGAGTTTGTACTTTAGGCTTGAACTTCCCACACGTGTTATTTG GCCCACATTGTGTTTGAAGAAACTTTGGGATTGGTTGCCAGTGCTTAAAAGTTAGGA CTTAGAAAATGGATTTCCTGGCAGGACGCGGTGGCTCATGCCCATAATCTCAGCACT TTGGGAGGCCTAGGAAGGTGGATCACCTGAGGTCCGGAGTTCAAGACTAACCTGGC CAACATGGTGAAACCCAGTATCTACTAGGACTGTTTGAATGAGGCTTCAGTACTTTA CAGAATCGTTGCCTGCACATCTTGGAAACACTTGCTGGGATTACTTCGACTTCTTAA CCCAACAGAAGGCTCGAGAAGGTATATTGCTGTTGACAGTGAGCGAAACGATATGG GCTGAATACAATAGTGAAGCCACAGATGTATTGTATTCAGCCCATATCGTTGTGCCT ACTGCCTCGGACTTCAAGGGGCTAGAATTCGAGCAATTATCTTGTTTACTAAAACTG AATACCTTGCTATCTCTTTGATACATTTTTACAAAGCTGAATTAAAATGGTATAAATT AAATCACTTTCAGCGCACTCGAATGTAGAAGTAGCAATATATAAATTATGCATTAAT GGGTTATAATTCACTGAAAAATAGTAACGTACTTCTTAACTTTGGCTTTCAGAGTTC GAACCAACGTGGCCTCAACCAGATTTGGAATGTCAAAAAGCAGAGTGTCTATTTGAT GAATTTGAGGAAATCTGGAACTTTGGGCCACCCAGGCTCTCTAGATGAGACCACCTA TGAAAGACTAGCAGAGGAAACGCTGGACTCTTTAGCAGAGTTTTTTGAAGACCTTGC AGACAAGCCATACACGTTTGAGGACTATGATGTCTCCTTTGGGAGTGGTGTCTTAAC TGTCAAACTGGGTGGAGATCTAGGAACCTATGTGATCAACAAGCAGACGCCAAACA AGCAAATCTGGCTATCTTCTCCATCCAGTGGACCTAAGCGTTATGACTGGACTGGGA AAAACTGGGTGTACTCCCACGACGGCGTGTCCCTCCATGAGCTGCTGGCCGCAGAG CTCACTAAAGCCTTAAAAACCAAACTGGACTTGTCTTCCTTGGCCTATTCCGGAAAA GATGCTTGAGGATCCCCCAGTACATGACCTTATGGGCTAGCGCTATGAAACGATATG GGCTGAATACAAATCACAGGCTATGAAACGATATGGGCTGAATACAAATCACAGGC TATGAAACGATATGGGCTGAATACAAATCACAGTGCAGGAGCTTTCTTATATCCACC TTCCTCCTTTTCTCTCAGCCCATCATCTAGCTACACAGTCTCCAGGGTAAGCTTTCAG AAAGGCAATCTCTTGTCTGTAAAACCTAAGCAGGACCAAGGCCAAGTTTCTTAGCCT GAAAAATGTGCTTTTCTGACTGAACTGTTCAGGCACTGACTCTACATATAATTATGC TTTTCTACCCCCTCACACTCAACACTTTGACTCCAGCAATCCCAAATCCCCAGATCCC TAAGTGTGCTGTGCTATTTTCACGTGGCTCTCAGACTTGGCCAGTGCTGTTTCCATTT TGGTCTTTATTCCCCACATCTCTGCCTGGGGGGTAGATTCTACCCTGAAAAATGTTCT TGGCACAGCCTTGCAAACTCCTCCTCCACTCAGCCTCTGCCTGGATGCCCTTGATTGT TCCATGTCCTCAGCATACCATGTTTGTCTTTCCCAGCACTGACCTACCATGTGTCACC CCTGCTTGGCTGTACCTTCCATGAGGCTAGGACTATGTGTCTCCTTTGTTGACTGCTG TTGCCCTAGCATCTTGCACAGTTCCTTGCACACAATTAGAGCTCTATAAATGTCAAA TAAATGTGTTATAATTATATGTTTAAGATAGTTGTTCAAATAAACTCTAAATAACCC CAACTCCAAGAGTGTTAGCAAGAAATATAAATTTTACAGAAGAATGGTTGGAGGTG GGTTGTGCGGACCGAGCGGCCGCAGGAACCCCTAGTGATGGAGTTGGCCACTCCCT CTCTGCGCGCTCGCTCGCTCACTGAGGCCGGGCGACCAAAGGTCGCCCGACGCCCG GGCTTTGCCCGGGCGGCCTCAGTGAGCGAGCGAGCGCGCAGCTGCCTGCAGG SEQ ID NO:13: hFXNP882 promoter CAGGACCACACCACTGCACTCCAGCCTGGGCAACAGAGTGAGACTCTGTCTCAAAC AAACAAATAAATGAGGCGGGTGGATCACGAGGTCAGTAGATCGAGACCATCCTGGC TAACACGGTGAAACCCGTCTCTACTAAAAAAAAAAAAAAATACAAAAAATTAGCCA GGCATGGTGGCGGGCGCCTGTAGTCCCAGTTACTCGGGAGGCTGAGGCAGGAGAAT GGCGTGAAACCGGGAGGCAGAGCTTGCAGTGAGCCGAGATCGCACCACTGCCCTCC AGCCTGGGCGACAGAGCGAGACTCCGTCTCAATCAATCAATCAATCAATAAAATCT ATTAACAATATTTATTGTGCACTTAACAGGAACATGCCCTGTCCAAAAAAAACTTTA CAGGGCTTAACTCATTTTATCCTTACCACAATCCTATGAAGTAGGAACTTTTATAAA ACGCATTTTATAAACAAGGCACAGAGAGGTTAATTAACTTGCCCTCTGGTCACACAG CTAGGAAGTGGGCAGAGTACAGATTTACACAAGGCATCCGTCTCCTGGCCCCACAT ACCCAACTGCTGTAAACCCATACCGGCGGCCAAGCAGCCTCAATTTGTGCATGCACC CACTTCCCAGCAAGACAGCAGCTCCCAAGTTCCTCCTGTTTAGAATTTTAGAAGCGG CGGGCCACCAGGCTGCAGTCTCCCTTGGGTCAGGGGTCCTGGTTGCACTCCGTGCTT TGCACAAAGCAGGCTCTCCATTTTTGTTAAATGCACGAATAGTGCTAAGCTGGGAAG TTCTTCCTGAGGTCTAACCTCTAGCTGCTCCCCCACAGAAGAGTGCCTGCGGCCAGT GGCCACCAGGGGTCGCCGCAGCACCCAGCGCTGG SEQ ID NO:14: hFXN 5’UTR AGGGCGGAGCGGGCGGCAGACCCGGAGCAGC SEQ ID NO:15: hFXN enhancer AATTCAAAGTTAGACCAGAATAGTGGTTCTCAACCAGGGGCAATTTTACTCCTTAGG GGACCTTTTCACAATGTCTGGAGACATTTTTGATTGTCACTATTGAATGGGAGAGCA GATACTACTGCCATCTAGTGGGTGGAGACCAAGAATGCTGCTAAACCACCTTACAAT GCATGGGACAACCACCACGACAGAGTTAGCCATGTGTTGCTTAACAACAGGGATAC ATTCTGGGAAATGCATCATTAGGT SEQ ID NO:16: hFXNpA13’UTR TGCAGGAGCTTTCTTATATCCACCTTCCTCCTTTTCTCTCAGCCCATCATCTAGCTAC ACAGTCTCCAGGGTAAGCTTTCAGAAAGGCAATCTCTTGTCTGTAAAACCTAAGCAG GACCAAGGCCAAGTTTCTTAGCCTGAAAAATGTGCTTTTCTGACTGAACTGTTCAGG CACTGACTCTACATATAATTATGCTTTTCTACCCCCTCACACTCAACACTTTGACTCC AGCAATCCCAAATCCCCAGATCCCTAAGTGTGCTGTGCTATTTTCACGTGGCTCTCA GACTTGGCCAGTGCTGTTTCCATTTTGGTCTTTATTCCCCACATCTCTGCCTGGGGGG TAGATTCTACCCTGAAAAATGTTCTTGGCACAGCCTTGCAAACTCCTCCTCCACTCA GCCTCTGCCTGGATGCCCTTGATTGTTCCATGTCCTCAGCATACCATGTTTGTCTTTC CCAGCACTGACCTACCATGTGTCACCCCTGCTTGGCTGTACCTTCCATGAGGCTAGG ACTATGTGTCTCCTTTGTTGACTGCTGTTGCCCTAGCATCTTGCACAGTTCCTTGCAC ACAATTAGAGCTCTATAAATGTCAAATAAATGTGTTATAATTATATGTTTAAGATAG TTGTTCAAATAAACTCTAAATAACCCCAACTCCAAGAGTGTTAGCAAGAAATATAAA TTTTACAGAAGAATGGTTGGAGGTGGEQUIVALENTS AND INCORPORATION BY REFERENCEAll references cited herein are incorporated by reference to the same extent as if each individual publication, database entry (e.g., Genbank sequences or GeneID entries), patent application, or patent, was specifically and individually indicated incorporated by reference in its entirety, for all purposes. This statement of incorporation by reference is intended by Applicants, pursuant to 37 C.F.R. §1.57(b)(1), to relate to each and every individual publication, database entry (e.g., Genbank sequences or GeneID entries), patent application, or patent, each of which is clearly identified in compliance with 37 C.F.R. §1.57(b)(2), even if such citation is not immediately adjacent to a dedicated statement of incorporation by reference. The inclusion of dedicated statements of incorporation by reference, if any, within the specification does not in any way weaken this general statement of incorporation by reference. Citation of the references herein is not intended as an admission that the reference is pertinent prior art, nor does it constitute anyadmission as to the contents or date of these publications or documents. While the inventionhas been particularly shown and described with reference to a preferred embodiment and various alternate embodiments, it is understood by persons skilled in the relevant art that various changes in form and details can be made therein without departing from the spirit and scope of the invention.

Claims

1. WHAT IS CLAIMED IS1. A therapeutic FXN polynucleotide construct comprising:a promoter fragment; an optional non mammalian based miRNA regulatory element and at least one cognate miRNA binding site; a human FXN coding sequence; a 3’ regulatory element; and a polyadenylation signal.

2. The polynucleotide construct of claim 1, wherein the human FXN coding sequence comprises the nucleotide sequence of SEQ ID NO:1 or SEQ ID NO:3, or a nucleotide sequence having at least 80% identity to SEQ ID NO:1 or SEQ ID NO:

3.

3. The polynucleotide construct of claim 1, wherein the polynucleotide construct encodes the amino acid sequence set forth in SEQ ID NO:

2.

4. The polynucleotide construct of claim 1 or 2, wherein the promoter fragment comprises SEQ ID NO:7, SEQ ID NO:13, or SEQ ID NO:14 or a nucleotide sequence having at least 90% identity to any of SEQ ID NO:7, SEQ ID NO:13, or SEQ ID NO:

14.

5. The polynucleotide construct of any of the previous claims, wherein the 3’ regulatory element comprises woodchuck hepatitis virus post-transcriptional regulatory element (WPRE3) SEQ ID NO:9 or a nucleotide sequence having at least 80% identity to SEQ ID NO: 9.

6. The polynucleotide construct of any of the previous claims, wherein the polynucleotideconstruct comprises, SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12, or a nucleotide sequence having at least 90% identity to SEQ ID NO:5, SEQ ID NO:6, SEQ ID NO: 11 or SEQ ID NO:12.

7. The polynucleotide construct of any of the above claims, further comprising at least oneadeno-associated virus (AAV) inverted terminal repeat (ITR).

8. The polynucleotide construct of claim 7, wherein the polynucleotide construct comprisestwo AAV ITRs.

9. A vector comprising the polynucleotide construct of any of the above claims.

10. The vector of claim 9, wherein the vector is a viral vector.

11. The vector of claim 9 or 10, wherein the vector is an adeno-associated virus (AAV) vector.

12. The vector of claim 11, wherein the AAV vector is an AAV9 vector.

13. A recombinant adeno-associated virus (rAAV), comprising the polynucleotide construct of any of claims 1 to 8 or the vector of any of claims 9-12.

14. The rAAV of claim 13, wherein the rAAV is AAV9.

15. A virion comprising the rAAV of claim 13 or 14.

16. A transformed cell comprising the polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9 to 12, the rAAV of claim 13 or 14, or the virion of claim 15.

17. A pharmaceutical composition comprising the polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9 to 12, the rAAV of claim 13 or 14, or the virion of claim 15 and a pharmaceutically acceptable carrier.

18. A method of treating Friedreich Ataxia (FA) and / or related disorders in a subject, the method comprising administering to the subject an effective amount of the polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9 to 12, the rAAV of claim 13 or 14, the virion of claim 15, or the pharmaceutical composition of claim 17.

19. A method of increasing mitochondrial iron transport and or respiration in a subjectdiagnosed with FA, the method comprising administering to the subject an effective amount of the polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9 to 12, the rAAV of claim 13 or 14, the virion of claim 15, or the pharmaceutical composition of claim 17.

20. The method of claim 18 or 19, wherein the administration is by intracerebral ventricularinjection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration to thesubject.

21. The method of any of claims 18-20, wherein administration does not result in an increase above baseline of any one or more of the integrated stress response (ISR) markers: Atf4, Asns,Fgf21, Gdf15 or Trib3 in cardiac or neuronal tissue.

22. The method of any one of claims 18-21, wherein the treatment results in an improvementin one or more symptoms associated with FA.

23. The method of claim 22, wherein the one or more symptoms associated with FA is selectedfrom awkward and unsteady movements, impaired muscle coordination, difficulty walking, poor balance, impaired sensory functions, loss of normal reflexes, dysarthria, spasticity, scoliosis, difficulty swallowing, hearing loss, vision loss, and fatigue.

24. The method of claim 22, wherein the treatment results in improved motor function.

25. The method of claim 22, wherein the treatment results in improved cardiac function.

26. The method of any one of claims 18-25, wherein treatment results in an increase of frataxin protein in the subject by at least 10%, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, or 100% relative to frataxin expression in the subject prior to treatment.

27. The polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9 to 12,the rAAV of claim 13 or 14, the virion of claim 15, or the pharmaceutical composition of claim17 for use in the treatment of Friedreich ataxia (FA), and / or an FA associated disorder in a subject.

28. The polynucleotide construct, vector, rAAV, virion or pharmaceutical composition for theuse of claim 27 wherein the polynucleotide construct, vector, rAAV, virion or pharmaceuticalcomposition is administered to the subject by intracerebral ventricular injection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration.

29. Use of the polynucleotide construct of any of claims 1 to 8, the vector of any of claims 9to 12, the rAAV of claim 13 or 14, the virion of claim 15, or the pharmaceutical composition ofclaim 17 in the manufacture of a medicament for the treatment of Friedreich ataxia (FA), and / oran FA associated disorder in a subject.

30. The use of claim 29 wherein in use the polynucleotide construct, vector, rAAV, virion orpharmaceutical composition is administered to the subject by intracerebral ventricular injection, intravenous administration, or by Deep Cerebellar Nuclei (DCN) administration.

31. The polynucleotide construct, vector, rAAV, virion or pharmaceutical composition forthe use of claim 27 or 28, or the use of claim 29 or 30, wherein in use administration does notresult in an increase above baseline of any one or more of the integrated stress response (ISR)markers: Atf4, Asns, Fgf21, Gdf15 or Trib3 in cardiac or neuronal tissue.

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