Plasmids, transgenes, vectors and medical uses comprising tissue non-specific alkaline phosphatase

Abstract

The present invention provides gene therapy plasmids and transgenes comprising soluble tissue non-specific alkaline phosphatase, recombinant virus vectors for delivery of said viral plasmids and transgenes and medical uses relating to the treatment of pyrophosphate deposition diseases and / or hypophosphatasia.

Description

FIELD OF THE INVENTION The present invention provides gene therapy plasmids and transgenes comprising soluble tissue non-specific alkaline phosphatase, recombinant virus vectors for delivery of said viral plasmids and transgenes and medical uses relating to the treatment of pyrophosphate deposition diseases and / or hypophosphatasia. Background of the invention Pyrophosphate deposition diseases are a group of disorders linked by build-up of extracellular inorganic pyrophosphate (PPi) due to a lack or decrease of hydrolysation of PPi by pyrophosphatases. Hypophosphatasia (HPP) is a rare and life-threatening genetic disorder characterized by seizures and defective mineralization, and results in bones that are soft and prone to fracture and deformity. Non-skeletal manifestations include pyridoxine-responsive seizures, hypercalcemia, hypercalciuria, myopathy, and dental manifestations. Mortality rates up to 73% from birth to 5 years of age have been reported in untreated patients. The prevalence of severe, moderate and mild HPP-subtypes is estimated in 1 / 300,000 (severe; perinatal / infantile), 1 / 2430 (moderate; infantile / childhood / odonto / adult) and 1 / 508 (mild; adult), respectively. (Mornet et al.(2011) Ann Hum Genet 75:439 ; Mornet et al. (2021) European Journal of Human Genetics 29:289). However, HPP may still be underdiagnosed. Another example of a Pyrophosphate deposition disease is Calcium Pyrophosphate Deposition Disease (CPPD), a form of arthritis caused by inflammatory response to calcium pyrophosphate crystals build up in the joints. Notably, CPPD can also develop in patients with HPP. The genetic defect underlying HPP lies in recessive mutations in the gene encoding tissue-nonspecific alkaline phosphatase (TNAP / TNALP / ALP; encoded by ALPL; National Center for Biotechnology Information (NCBI) gene number 249). TNAP is expressed rather ubiquitously at varying levels but foremost in human liver, bone and kidney. The biochemical hallmark of HPP is subnormal alkaline phosphatase activity in 1 serum (hypophosphatasemia), and this functional deficiency leads to elevated blood or urine levels of three phosphocompounds: pyridoxal 5'-phosphate (PLP), inorganic pyrophosphate (PPi), and phosphoethanolamine (PEA). The ratio of extracellular PPi to Pi is crucial in the mineralization process and is regulated by the interaction of three phosphatases present in matrix vesicles: the mineralization promotors TNAP and phosphatase orphan 1 (PHOSPHO1), and the mineralization inhibitor nucleotide pyrophosphatase / phosphodiesterase (NPP). TNAP utilizes its pyrophosphatase function to hydrolyze PPi, the potent mineralization inhibitor, providing Pi, which is incorporated into mineral (hydroxyapatite). A lack of TNAP activity in bone thus results in under-mineralized bone tissue. TNAP hydrolyzes pyridoxal 5'-phosphate (phospho-Vitamin-B6; PLP) to pyridoxal to enter cells. Pyridoxal is converted back to PLP once inside the cell. When TNAP is deficient, PLP thus accumulates in the circulation, while intracellular brain PLP-levels can be low, resulting in neuronal PLP-deficiency despite high levels of circulating PLP. Vitamin B-6 is involved in the biosynthesis of most neurotransmitters. Decreased gamma-aminobutyrate (GABA) appears to be most directly related to the development of seizures in vitamin B-6 deficiency. While effects on GABA metabolism appear to be the major contributor to seizures, multiple other intra- and extra-cellular metabolic systems may be affected directly and / or indirectly by altered vitamin B-6 hydrolysis and uptake resulting from variations in alkaline phosphatase activity (Coburn, Subcell Biochem 2015:76:207-38). Parvoviridae are a family of viruses composed of a single-stranded DNA genome encapsidated in a 25 nm non-enveloped capsid. Gene therapy vectors based on Parvoviridae, such as adeno-associated viruses (AAV, belonging to the genus dependoparvovirus), have proven safe and efficacious in numerous clinical trials (Kuzmin et al. (2021) Nature Reviews Drug Discovery 20:173-174). Hence, viral gene therapy using Parvoviridae such as AAV could provide a suitable alternative to treatment with enzyme replacement therapy (ERT). Preclinical studies testing AAV based TNAP expression show amelioration of mortality, seizures and pathological bone structure in a mouse model of HPP where TNAP is expressed from a ubiquitous chicken beta-Actin (CBA) promoter when injected into muscle tissue to cross-correct TNAP deficiency in other tissues (Nakamura-Takahashi et al. (2020) Calcif Tissue Int 106:665-677). However, off-target activity of TNAP can lead to ectopic mineralization, especially in endothelial cells of the vasculature. In vivo studies show that TNAP upregulation in endothelial cells results in vascular calcification, leading to heart failure and reduced life expectancy (Sheen et al. (2014) JBMR 30(5):824-836). Another barrier to effective virus-based delivery of TNAP is that a high dose of AAV is necessary to establish effective plasma levels of the transgene. Previous studies showed that high doses of 4.5 x 1012 vector genomes (vg) per body in newborn mice [approximated dose / body weight (2 gram): 2.25 x 1015 vg / kg] were necessary to reach blood activity levels of 20 U / ml of alkaline phosphatase (ALP) in blood and provide phenotypic improvements when expressing TNAP from a ubiquitous chicken beta-Actin promoter (Nakamura-Takahashi et al. (2020), reviewed by Sawamoto et al. (2020) Curr Osteoporos Rep 18(5):515-525). Hence, it is desirable to develop an effective gene therapy approach that enables bone targeting of TNAP while reducing the risk of off-target effects. Objectives and Summary of the Invention The inventors have developed a viral plasmid comprising a recombinant gene expression cassette encoding soluble TNAP (sTNAP) using a virus-based delivery mechanism that enables cross-correction of TNAP deficiency in brain and bone while minimizing off-target effects. Surprisingly, the inventors found that using the claimed viral plasmid, sufficient plasma levels of active sTNAP could be reached for effective treatment at clinically feasible dose levels. Currently, the only HPP-treatment approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) is enzyme replacement therapy (ERT) with asfotase alfa (Strensiq®). ERT is administered subcutaneously three to six times a week for life. Thus, there is a need for improved treatment approaches that reduce or obviate the lifelong burden of daily treatment on HPP patients. In order to eliminate the burden of daily ERT therapy, the inventors have developed a viral plasmid comprising a recombinant gene expression cassette that is suitable for delivery of a bone-mineral targeted TNAP in vivo. In contrast to treatment with ERT therapy, the viral plasmid of the invention is only administered once and provides a longterm stable therapeutic effect. Hence, in a first aspect, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In a particular embodiment, the sTNAP is a functional variant of TNAP. More particularly, in one embodiment, sTNAP comprises the soluble extracellular catalytic domain of TNAP. In one embodiment, sTNAP lacks a GPI membrane anchor. In one embodiment, the regulatory element of b) is a tissue-specific promoter. Tissue-specific promoters comprise one or more promoter and / or enhancer elements that are active in one or more specific tissues. A tissue specific promoter may be highly active in one cell type, e.g. in hepatocytes, and less active in other tissues. A specific promoter may have been highly active in different cell types during embryonic development, but is only active in one specific tissue in adults. Tissue-specific promoters are advantageous because they reduce off-target expression of the transgene. On the other hand, tissue non-specific promoters, i.e. ubiquitous promoters, often provide a stronger transgene expression that is necessary to reach adequate activity levels of a transgene in gene therapy applications. In one embodiment, the regulatory element of b) is a liver-specific promoter. Exemplary liver-specific promoters are HLP (hybrid liver-specific promoter) and HCB (synthetic liver-specific promoter). In one embodiment, the polynucleotide encoding the regulatory element is upstream of the polynucleotide encoding sTNAP. In a preferred embodiment, the liver-specific promoter is HLP. The inventors have found that targeting the expression of sTNAP comprising a hydroxyapatite binding domain to the liver is an effective way of providing sufficient levels of TNAP in bone tissue due to crossing over of the enzyme. At the same time, constitutive expression of sTNAP in other tissues is avoided, therefore reducing the risk of ectopic mineralization. To this end, the polynucleotide a) is codon-optimized for liver expression. In one embodiment, the polynucleotide a) comprises a nucleic acid sequence that is at least 90% identical to the nucleic acid sequence set forth in SEQ ID NO: 1. In one embodiment, the polynucleotide a) encodes an amino acid sequence that is at least 70% identical to the amino acid sequence set forth in SEQ ID NO. 2. One of the greatest challenges of gene therapy using viral delivery methods is to reduce viral load, i.e. virus genomes per injection, while ensuring effective expression levels and plasma activity of the transgene, and simultaneously avoiding off-target effect. Hence, the viral plasmid also comprises a stabilizing domain that prolongs the half-life of 5 the transgene in vivo. The inventors have found that by adding a fragment crystallizable domain (Fc domain) to the recombinant expression cassette, they could stabilize the transgene-product in vivo and therefore boost activity levels and reduce the need for excessive viral load to overexpress the transgene. In one embodiment, the Fc domain of c) comprises the amino acid sequence of an Fc domain from a mammalian IgG, IgA or IgD antibody. Preferably, the Fc domain of c) comprises the amino acid sequence of an Fc domain from a human IgG antibody. In one embodiment, the Fc domain of c) comprises a nucleic acid sequence that is at least 70% identical to the nucleic acid sequence of SEQ ID NO: 5. The plasmid of the invention enables enrichment of the transgene product in the symptomatic tissue, i.e. in bone tissue and bone mineral, without the need to use a virus that targets bone tissue or a bone-cell specific promoter. Virus targeting to bone or use of a bone-specific promoter are not practicable, because the majority of bone is made up of highly mineralized tissue, i.e. inorganic material, which undergoes perpetual renewal. The inventors have shown that by using a liver-targeted plasmid with a hydroxyapatite binding domain, the enzyme activity in circulation and hence in vascularized bone tissue is sufficient to treat bone-demineralization phenotypes as well as reducing or preventing seizures. To enable crossing-over of the fusion protein to the target tissue, i.e. bone tissue and bone mineral, the fusion protein comprises a targeting peptide which is a hydroxyapatite binding domain. Hydroxyapatite is a mineral that only exists in bone and teeth and therefore provides a selective target for drug delivery to these tissues. Hence, while the viral plasmid is provided at a low dosage, specific targeting of the therapeutic protein to the bone mineral, which mainly consists of hydroxyapatite, ensures that sufficient concentrations of the enzyme can be reached in the bone tissue and bone mineral for effective treatment. A hydroxyapatite binding domain can be an acidic oligopeptide. In one embodiment, the hydroxyapatite binding domain of d) is selected from the group consisting of poly aspartic acid (D) and poly-glutamic acid (E). In a preferred embodiment, the hydroxyapatite binding domain of d) is poly-aspartic acid (D) or poly-glutamic acid (E) comprising between six and fifteen continuous residues. In one embodiment, the hydroxyapatite binding domain of d) is a poly aspartic acid comprising between six and fifteen continuous residues, i.e. D6 to D15. In a particular embodiment, the hydroxyapatite binding domain of d) is decapeptide aspartic acid, i.e. D10. In one embodiment the hydroxyapatite binding domain is C-terminal relative to sTNAP. In one embodiment, the expression product of the recombinant gene expression cassette is a fusion protein comprising in order from N-terminal to C-terminal the sTNAP, the Fc domain and the hydroxyapatite binding domain. The regulatory elements may be located upstream and / or downstream of the fusion protein. The plasmid comprising the recombinant gene expression cassette is suitable for in vivo delivery by a virus of the family Parvoviridae. Hence, the recombinant gene expression cassette is adjacent to at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In most cases, the recombinant gene expression cassette is flanked by two ITRs, one 3’ ITR and one 5’ ITR. In some cases, one ITR can be sufficient for virus production. The at least one ITR can be from a wild-type virus variant, a non-naturally occurring virus variant, a synthetic virus variant or an engineered virus variant. In one embodiment, the at least one ITR is from a virus of a genus selected from the group consisting of amdoparvovirus, aveparvovirus, bocaparvovirus, copiparvovirus, dependoparvovirus, erythroparvovirus, and tetraparvovirus. In a preferred embodiment, the at least one ITR is from a virus of the genus dependoparvovirus. In an even more preferred embodiment, the at least one ITR is from an adeno-associated virus (AAV). In one embodiment, the at least one ITR is from an AAV selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, AAV13. In another embodiment, the at least one ITR is AAV2 or AAV8, preferably, the at least one ITR is from AAV2. In a preferred embodiment, the at least one ITR is two ITRs flanking the recombinant gene expression cassette, a 5’ ITR and a 3’ ITR. Hence, the recombinant gene expression cassette is flanked by paired ITRs. In one embodiment, the nucleic acid sequence of the 5’ ITR is at least 90% identical to the nucleic acid sequence set forth in SEQ ID NO: 7 and the nucleic acid sequence of the 3’ ITR is at least 90% identical to the nucleic acid sequence set forth in SEQ ID NO: 8. In one embodiment, the 5’ ITR and 3’ ITR nucleic acid sequences are reversecomplement. In one embodiment, the 5’ ITR and 3’ ITR nucleic acid sequences are completely reverse-complement. The inventors have found that they can achieve an even more precise expression regulation of the transgene by making use of endogenously expressed miRNA. By adding a binding site to the 3’UTR of the transgene expression cassette which is recognized by a miRNA that is highly expressed in off-target tissues, but not or only very lowly expressed in the target tissue, the inventors were able to further reduce off-target risks of the transgene. Hence, in one embodiment, the recombinant gene expression cassette further comprises one or more miRNA binding sites. The miRNA binding sites become a functional part of the transcript upon transcription of the recombinant gene expression cassette. In one embodiment, the one or more miRNA binding sites are located between the hydroxyapatite binding domain and the 3’ end of the recombinant gene expression cassette. Hence, in one embodiment, the one or more miRNA binding sites are located between the end of the transgene (encoding the hydroxyapatite binding domain) and the 3’ ITR of the recombinant gene expression cassette. In one particular embodiment, the one or more miRNA binding sites are recognised by micro RNA (miR) miR126-3p or miR126-5p, preferably miR126-5p. In one embodiment, the one or more miRNA binding sites comprise a nucleic acid sequence that is at least 70% identical to the nucleic acid sequence as set forth in SEQ ID NO: 9. In one embodiment, the recombinant gene expression cassette comprises two miRNA binding sites. In another embodiment, the recombinant gene expression cassette of the viral plasmid further comprises a polynucleotide comprising one or more 5’ intron sequences. In another embodiment, the recombinant gene expression cassette of the viral plasmid further comprises a polynucleotide comprising one or more Woodchuck Hepatitis Virus posttranscriptional regulatory element (WPRE) sequences. In one embodiment, WPRE sequences enhance transgene expression compared to transgene expression cassettes not comprising a WPRE element. In another aspect, the invention also relates to an isolated polynucleotide comprising the viral plasmid of the invention. The polynucleotide is suitable for packaging within a virus capsid, thus providing a virus comprising a plasmid-borne transgene genome and a capsid shell. Hence, in another aspect, the invention relates to a recombinant virus comprising the recombinant gene expression cassette of the invention and a capsid. In one embodiment, the capsid is from a virus of the family Parvoviridae. Preferably, the capsid is from a virus of the family Parvoviridae exhibiting liver tropism. The capsid can be a wild-type capsid, a non-naturally occurring capsid, a synthetic capsid or an engineered capsid. Preferably, the capsid is from AAV8. Hence, in a particular embodiment, the capsid is from AAV8 and the recombinant gene expression cassette is flanked by two ITRs of AAV2. In another embodiment, the recombinant virus does not exhibit muscle tropism. In another aspect, the invention also relates to a host cell comprising the viral plasmid, the isolated polynucleotide or the recombinant virus of the invention. In a further aspect, the invention also relates to a pharmaceutical composition comprising the viral plasmid, the isolated polynucleotide, the recombinant virus or the host cell of the invention, and optionally one or more excipients. One objective of the invention is to provide an improved treatment for hypophosphatasia and / or pyrophosphate deposition diseases. Hence, another aspect of the invention is to provide a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae', for use as a medicament. Furthermore, the invention provides an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for use as a medicament. In another aspect of the invention is to provide a plasmid of the invention for use in gene therapy. Hence, the invention also provides an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for use in gene therapy. Another aspect of the invention relates to a plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for use in the treatment of pyrophosphate deposition diseases in a subject in need thereof. The invention also provides the use of a plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for the manufacture of a medicament for the treatment of pyrophosphate deposition diseases. In one embodiment, the treatment increases mineralization in bone tissue in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. In another embodiment, the treatment increases the ratio of extracellular Pi to PPi in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. In a preferred embodiment, the pyrophosphate deposition disease is hypophosphatasia (HPP). The plasma activity level of Strensiq® (commercially available asfotase alfa ERT product) at which a sufficient therapeutic effect is reached is known. Therefore, the inventors were able to compare the therapeutic effect of the viral plasmid of the invention with Strensiq® by comparing the plasma activity level of the enzyme. In particular, the inventors show that a low dose of only 1 x 1012 vg / kg in mice [approximated dose / body (25 gram): 2.5 x 1010vg / body] provides at least the same pharmacodynamic effect / activity as either a single therapeutic dose of Strensiq®, a daily dose of Strensiq® for 4 weeks or for 6 weeks. Hence, in one embodiment, the recombinant virus for use according to the invention is administered at a dose of about 1 x 1012 vg / kg, wherein the recombinant virus comprises an AAV8 capsid. Therefore, the starting dose for a human trial with the recombinant virus for use according to the invention is between 2 x 1013 vg / kg to 3 x 1013 vg / kg (i.e. 20x - 30x of the mouse dose), wherein the recombinant virus comprises an AAV8 capsid. A lower starting dose for a human trial may be chosen if the virus exhibits an improved liver tropism compared to AAV8, for example, by directed evolution of the capsid or through use of a targeting peptide. The starting dose for a human trial with the recombinant virus for use according to the invention is below 3 x 1013 vg / kg. In one embodiment, the starting dose for a human trial with the recombinant virus for use according to the invention is below 3 x 1013 vg / kg and the recombinant virus exhibits an improved liver tropism compared to AAV8. Hence, in one embodiment, the recombinant virus for use according to the invention is administered to a subject in need thereof at a dose of up to 2 x 1013 to 3 x 1013 vector genomes per kg (vg / kg). In one embodiment, the recombinant virus for use according to the invention is administered to a subject who has previously received enzyme replacement therapy for hypophosphatasia. In one embodiment, the subject has previously received at least six daily doses of enzyme replacement therapy for hypophosphatasia. In a particular embodiment, the recombinant virus for use according to the invention is administered once. Figure Legends Figure 1: Addition of Fc domain to the gene therapy cassette results in higher serum sTNAP activity. A: ALP serum activity in mU / mL in the serum of wild-type C57 / BL6 mice at 28 days post injection in mice that were injected with AAV8-STNAP-FC-D10 (L01, LaudaOI), AAV8-STNAP-D10 (L02, Lauda02) or AAV8-STNAP (L03, Lauda03) at >6-weeks of age. ** p<0.01, Unpaired t-test (two tailed) with Welch's correction; mean +1- SD. B: Vector copy number in liver tissue per pg genomic DNA (gDNA). C: Schematic depiction of the transgenes used in this and the following experiments. Figure 2: Addition of D10 domain to the gene therapy cassette results in interaction with bone mineral (hydroxyapatite). Supernatant ALP activity in mU / mL after treatment of Huh-7 cells with the indicated experimental constructs AAV8-STNAP-D10 (Lauda02), AAV8-STNAP (Lauda03) or the enzyme Asfotase Alfa (Strensiq®) at either 10mU / ml or40mU / ml. Figure 3: AAV-sTNAP-Fc-D10 confers efficacious serum sTNAP activity in TNAP deficient mice into adulthood. A: ALP serum activity in mU / mL in the serum ofALP- / _ mice and controls at 28 days post injection in mice that were injected with AAV8-STNAP-FC-D10 (L01, LaudaOI) as newborns or treated daily by enzyme replacement therapy (ERT) with 8.2 mg / kg / d Asfotase Alfa (Strensiq®). **** p<0.0001, ns, not significant, Unpaired t-test (two tailed) with Welch's correction; mean +1- SD. B: ALP serum activity in mU / mL in the same mice over time in weeks. Figure 4: Liver directed transgene AAV-sTNAP-Fc-D10 confers survival in newborn TNAP deficient mice and can replace enzyme replacement therapy. A: Overall survival of ALP' / _ mice receiving daily ERT for 59 days (ERT d1-d59), for 28 days (ERT d1-d28), receiving injection of the gene therapy vector after 28 days of ERT (ERT d1 -d28 □ GT d29), receiving injection of the gene therapy vector at day 2 (GT d2) or ALP' / _ without treatment (TNAP KO mouse) as negative control and ALP+ / + littermates as positive control. Test article: Archl 1 1e14vg / kg intravenously (i.v.) on day 2 post partum [approximated dose / body (2 gram): 2 x 1011 vg / body]; ERT dose 8.2 mg / kg / d subcutanously (s.c.) ERT, enzyme replacement therapy; GT gene therapy. Daily dose from day 1 to day 59, or day 1 to day 28. ERT discontinuation followed by single dose Archl 1 or buffer on day 29. B: Schematic depiction of the transgenes Arch04 and Archl 1 used in this and the following experiments. Figure 5: Liver directed transgene AAV-sTNAP-Fc-D10 confers pharmacodynamic benefit in serum activity and bone growth in TNAP deficient mice and can replace enzyme replacement therapy. A: ALP serum activity in mU / mL in the serum of ALP'A mice and controls as described above for Figure 4. B: Femur length in mm in mice at study end. Holm-Sidak's multiple comparison test (* <0.05, *** <0.0001) Figure 6: Transduction of transgene AAV8-HLP-sTNAP*-FC-D10-MiRBS (Archil) is specific in targeted liver tissue over non-target tissue when treated as newborn or juvenile mouse. TNAP transgene copies per pg gDNA, or RNA expression levels measured in liver, aorta, quadriceps and heart as indicated in animals injected with AAV8-HLP:sTNAP-FC-D10 (Arch04) or AAV8-HLP-sTNAP*-FC-D10-MiRBS (Archil). Figure 7: miRNA expression profiling. Quantitative Real-Time PCR using probes detecting a panel of different miRNAs was performed on liver, vasculature and bone cell lines. Plot shows Ct values of miRNA expressed in the cell lines indicated in Table 1. Figure 8: Addition of miRNA binding sites to AAV-sTNAP-Fc-D10 results in reduced off-target expression of the transgene. Supernatant ALP activity in mU / mL after treatment of HepG2 cells (left, liver cells, on-target) or HUVEC cells (right, vascular cells, off-target) with the indicated experimental constructs AAV6-CMV:sTNAP-FC-D10 (L01), Senna14 (S14, AAV6-CMV:sTNAP-FC-D10-miRBS with 2x miRNA binding sites) or Senna08 (S08, AAV6-CMV:sTNAP-FC-D10-miRBS with 4x miRNA binding sites). Figure 9: Dose-exposure relationship in mice suggests highly efficacious sTNAP activity levels in plasma. ALP serum activity in mU / mL in the serum of wild-type mice injected once intravenously with AAV8-HLP-sTNAP*-FC-D10-MiRBS (Archl 1) at the indicated dose level, or treated subcutaneously with enzyme replacement therapy (ERT, 8.2 mg / kg / d Asfotase Alfa (Strensiq®) either once (single dose, wild-type mouse), or daily for 4 weeks or 6 weeks (Alpl" / _ mouse). Figure 10: Proof of principle study design in the TNAP deficient mouse. Figure shows study design using six treatment groups: 1) WT (Alpl+ / +); 2) KO (knock-out, Alpl- / -) untreated; 3) KO (Alpl- / -) treated with ERT daily from day 2 to day 59 “ERT d1-d59”; 4) KO (Alpl- / -) treated with ERT daily for only half of the study, between day 2 and day 28 “ERT d1-d28”; 5) KO (Alpl- / -) treated with ERT daily for only half of the study, between day 2 and day 28, followed by GT or vehicle on day 29 “ERT d1-d28 GT d29”; 6) KO (Alpl- / -) treated with GT on day 2 at the start of the study “GT d2”. ERT, enzyme replacement therapy - AA, asfotase alfa; daily dosing with asfotase alfa 8.2 mg / kg / d (subcutaneous). GT, gene therapy - Archl 1 (A11) single intravenous infusion (1 x 1014 vg / kg). Figures 11-12: Bone biomechanical testing. Ex-vivo analyses of Archl 1 treated and / or asfotase alfa treated groups. One-way ANOVA followed by Tukey's multiple comparisons test. Significant group differences are indicated (* p<0.05; ** p<0.01; *** p<0.0001; **** p<0.0001). ERT d1-d59: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d); ERT d1-d28: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d) to day 28; ERT d1-d28-GT d29: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d) to day 28, followed by single dose Archil on day 29 (i.v. 1e14 vg / kg); GT d2: single dose Archil on day 29 (i.v. 1e14 vg / kg). Figures 13-15: Micro-computed tomography. Ex- vivo analyses of Archil treated and or asfotase alfa treated groups. One-way ANOVA followed by Tukey's multiple comparisons test. Significant group differences are indicated (* p<0.05; ** p<0.01; *** p<0.0001; **** p<0.0001). BMD, Bone Mineral Density; BV, bone volume; TV, tissue volume; Tb.N., trabecular number; Tb.Th; trabecular thickness; Tb.Sp., trabecular separation. ERT d1-d59: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d); ERT d1-d28: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d) to day 28; ERT d1-d28-GT d29: daily treatment with asfotase alfa (s.c. 8.2 mg / kg / d) to day 28, followed by single dose Archil on day 29 (i.v. 1e14 vg / kg); GT d2: single dose Archil on day 29 (i.v. 1e14 vg / kg). Ct.Ar, cortical bone area; Ct.Th; cortical thickness; Ct.Po, cortical bone porosity. Figure 16: Von Kossa staining of high dose and vehicle mouse liver and mouse aorta FFPE sections. A: Von Kossa staining of wild-type mouse femur section. Dark areas show precipitation of silver ions reacting with phosphates and carbonates in calcium deposits. B: Von Kossa staining of liver of mice having received high dose of AAV carrying Archil transgene (top row) or vehicle control (bottom row). C: Von Kossa staining of aorta of mice having received high dose of AAV carrying Archl 1 transgene (top row) or vehicle control (bottom row). Scalebars are 1000pm for femur section, 5mm for liver sections and 500pm for aorta sections. Figure 17: Anti-human Alkaline Phosphatase detection in AAV treated mouse liver and aorta FFPE sections. Top left: specific human alkaline phosphatase signal in livers of mice injected with a high dose of AAV carrying Archl 1 transgene. Bottom left: human alkaline phosphatase background signal in livers of mice injected with vehicle. Top right: human alkaline phosphatase background signal in aorta of mice injected with a high dose of AAV carrying Archil transgene. Bottom right: human alkaline phosphatase background signal in aorta of mice injected with vehicle. Images show anti-human Alkaline Phosphatase antibody signal in the cytoplasm of positive cells and DAPI staining of nuclei. Scalebars are 200pm for liver sections and 50pm for aorta sections. DETAILED DESCRIPTION OF THE INVENTION Definitions Before the invention is described in detail with respect to some of its preferred embodiments, the following general definitions are provided. The present invention as illustratively described in the following may suitably be practiced in the absence of any element or elements, limitation or limitations, not specifically disclosed herein. The present invention will be described with respect to particular embodiments and with reference to certain figures, but the invention is not limited thereto but only by the claims. Where the term “comprising” is used in the present description and claims, it does not exclude other elements. For the purposes of the present invention, the term “consisting of” is considered to be a preferred embodiment of the term “comprising of”. If hereinafter a group is defined to comprise at least a certain number of embodiments, this is also to be understood to disclose a group which preferably consists only of these embodiments. Where an indefinite or definite article is used when referring to a singular noun, e.g. “a”, “an” or “the”, this includes a plural of that noun unless something else is specifically stated. The terms “about” or “approximately” in the context of the present invention denote an interval of accuracy that the person skilled in the art will understand to still ensure the technical effect of the feature in question. The term typically indicates deviation from the indicated numerical value of ±10%, and preferably of ±5%. Technical terms are used by their common sense. If a specific meaning is conveyed to certain terms, definitions of terms will be given in the following in the context of which the terms are used. As used herein, the term „Parvoviridae” refers to a family of viruses. Parvoviridae are small, icosahedral, non-enveloped viruses of 18-26 nm in diameter that contain a single molecule of linear, negative- or positive-sense single-standed DNA (ssDNA). Parvoviridae are among the smallest, simplest eukaryotic viruses and fall into two groups: defective viruses that are dependent on a helper virus for replication; and autonomous, replication-competent viruses. The family Parvoviridae comprises two subfamilies, the Parvovirinae, which infect vertebrates and the densovirinae, which infect invertebrates. Currently, eight genera are associated with the subfamily Parvovirinae, which are the genera amdoparvovirus, aveparvovirus, bocaparvovirus, copiparvovirus, dependoparvovirus (e.g. adeno-associate virus), erythroparvovirus (e.g. B19 virus), protoparvovirus (e.g. canine parvovirus, feline parvovirus), and tetraparvovirus. The term “adeno-associated virus” or "AAV" as used herein refers to a virus of the family Parvoviridae, subfamily Parvovirinae, genus dependoparvovirus. “AAV” may be used to refer to the naturally occurring wild-type virus itself or derivatives thereof. The term covers all subtypes, serotypes and pseudotypes, and both naturally occurring and recombinant, synthetic or engineered variants. Furthermore, "AAV" refers to both the genetic components of the virus, e.g., the genome (positive or negative) and RNA transcripts thereof (either sense or antisense), proteins encoded by the genome (including structural and nonstructural proteins), and viral particles. The term "adeno-associated virus" (AAV), includes but is not limited to, AAV serotype 1, AAV serotype 2, AAV serotype 3 (including serotypes 3 A and 3B), AAV serotype 4, AAV serotype 5, 17 AAV serotype 6, AAV serotype 7, AAV serotype 8, AAV serotype 9, AAV serotype 10, AAV serotype 11, AAV serotype 12, AAV serotype 13, AAVrh8, AAVrhlO, AAVrh.74, snake AAV, avian AAV, bovine AAV, canine AAV, equine AAV, ovine AAV, goat AAV, shrimp AAV, those AAV serotypes and clades disclosed by Issa et al. (2023) Cells 12(5):785 and Colon-Thillet et al. (2021) Virol J 18:85, and any other AAV occuring in nature (natural AAV isolate), or artifically designed (rational design, directed evolution) AAV capsid now known or later discovered. One of the identifying characteristics of Parvoviridae is the encapsidation of a singlestranded DNA (ssDNA) genome that can be either the sense or anti-sense strand. In the case of AAV, the separate plus or minus polarity strands are packaged with equal frequency, and either is infectious. The small (about 4.8 kilobases) ssDNA genome consists of two open reading frames, Rep and Cap, flanked by two 145 base ITRs (inverted terminal repeats). Rep and Cap are translated to produce multiple distinct proteins (e.g., Rep78, Rep68, Rep52, and Rep40, required for the AAV life cycle; and VP1, VP2, and VP3, the capsid proteins). When constructing a nucleic acid to be delivered using AAV, the exogenous nucleic acid (e.g., an immunogenic polypeptide transgene) is placed between the two inverted terminal repeats (ITR), and Rep and Cap typically are supplied in trans. Being helper dependent, the adeno-associated viruses generally require a helper virus for a productive infection. The term “inverted terminal repeat (ITR)” or “inverted terminal repeats (ITRs)” as used herein refers to nucleic acid sequences that are a component of a Parvoviridae transfer plasmid. The ITR regions are terminal repeats containing palindromic sequences that form hairpin-like structures. They usually occur in pairs of reverse-complement sequences and flank the genome of the virus on the 3’ and 5’ end. The ITR sequences contain the origin of replication and packaging signals. The nucleic acid sequence between the two ITR sequences, usually referred to as the genome or, in the case of a recombinant virus, the transgene, gets packaged into the virus. In the case of this particular invention, the gene expression cassette, which is flanked by ITRs, is packaged into the virus and comprises coding regions, signaling domains and regulatory regions. AAV virus have two ITR sequence of 145 bases each. The sequence of the ITR varies by virus species and, for example within species of AAV, by serotype. The terminal sequences of AAV are called homotelomeric termini, which refers to the occurance of two hairpins that are the same, i.e. perfectly reverse-complement sequences. The terminal sequences of some Parvoviridae, such as protoparvovirus, bocaparvovirus and amdoarvovirus, are heterotelomeric, i.e. not the same, and are referred to as “left-end hairpin (LEH)” and “right-end hairpin (REH)”. Whenever the term “ITR” is used in the present application, it may also refer to these heterotelomeric terminal structures. “Recombinant AAV” or “rAAV” refers to an engineered virus used as vector for in vitro or in vivo gene delivery. rAAVs are typically devoid of the rep gene and comprise an encapsidated genome which carries a therapeutic gene expression cassette in place of the genes necessary for virus production. The AAV genome is flanked by two ITRs at the ends that serve as the viral origins of replication and the packaging signal. In a rAAV vector, the only sequences of viral origin are the ITRs, which are needed to guide genome replication and packaging during vector production. The ITR-flanked rAAV genome can be cloned into plasmids and manipulated using standard molecular cloning techniques. Another version of rAAV is the self-complimentary AAV (scAAV), in which the coding region has been designed to form an intra-molecular double-stranded DNA template, thereby circumventing the need for second strand synthesis. The packaging capacity of a scAAV is about 2.4 kilobases, which is half of that of a typical rAAV (4.8 kilobases). In order to produce an AAV virus, typically, three plasmids are needed. Firstly, a packaging plasmid which contains the structural and packaging genes, this includes nucleic acid sequences encoding capsid proteins. Secondly, an adenoviral helper plasmid which contains proteins needed for the virus to replicate, since AAV depends on proteins from other viruses, e.g. adenovirus, to replicate. Thirdly, a transfer plasmid, which contains the viral genome or transgene and carries the ITRs as a packaging signal. In the case of the present invention, the transfer plasmid is referred to as “viral plasmid” because it comprises the ITR sequences and the transgene, i.e. the recombinant gene expression cassette, for packaging. The ITR sequences and capsid protein genes can be from different species of Parvoviridae or from different serotypes of AAV. In some embodiments, the nucleic acid sequence encoding the ITRs and the nucleic acid sequence encoding the capsid proteins are from the same virus serotype. A "helper virus" for AAV refers to a virus that allows AAV (e.g., wild-type AAV) to be replicated and packaged by a mammalian cell. A variety of such helper viruses for AAV are known in the art, including adenoviruses, herpes viruses and poxviruses such as vaccinia. The adenoviruses encompass a number of different subgroups, although Adenovirus serotype 5 of subgroup C is most commonly used. As used herein, the term "serotype" refers to a virus, such as AAV, which is identified by and distinguished from other viruses of the same genus based on capsid protein reactivity with defined antisera. For example, serotype AAV2 is used to refer to an AAV which contains capsid proteins encoded from the cap gene of AAV 2. As used herein, the term “capsid protein” refers to a protein product of an open reading frame (ORF) encoded by the ssDNA genome of Parvoviridae, often termed “cap” ORF. The cap ORF encodes three capsid proteins Viral Protein 1 (VP1), VP2 and VP3, that are produced via differential splicing of the mRNA and use of alternate translational start codons. "Packaging" as used herein refers to a series of subcellular events that results in the assembly and encapsidation of a cargo, e.g. a viral genome or recombinant viral genome or transgene. Thus, when a suitable polynucleotide is introduced into a packaging cell line under appropriate conditions, it can be assembled into a viral particle. The encapsidating protein shell is referred to as capsid. The capsid or shell has an inner and outer surface. The outer surface of the capsid is the part of the shell that is in contact with the environment. As used herein, “tropism” refers to the specificity of a capsid protein present in a virus or virus-like particle for infecting a particular type of cell or tissue. The tropism of a capsid for a particular type of cell or tissue may be determined by measuring the ability of a virus or virus-like particle comprising the capsid protein to infect or to transduce a particular type of cell or tissue, using standard assays that are well-known in the art. The term “transduction” refers to a process for the introduction of an exogenous polynucleotide, e.g., a transgene in a viral vector, into a host cell leading to expression of the polynucleotide, e.g., the transgene, in the cell. Altered expression or persistence of a polynucleotide introduced via the virus can be determined by methods well known to the art including, but not limited to, protein expression, e.g., by ELISA, flow cytometry and Western blot, measurement of and DNA and RNA production by hybridization assays, e.g., Northern blots, Southern blots and gel shift mobility assays. Other methods used for the introduction of the exogenous polynucleotide include well-known techniques such as transfection, lipofection, viral infection, transformation, and electroporation, as well as non-viral gene delivery techniques. The introduced polynucleotide may be stably or transiently maintained in the host cell. A viral vector may also be referred to as “virion” or “viral particle”. The term “recombinant gene expression cassette” as used herein refers to a nucleic acid sequence that is part of a DNA plasmid and comprises a gene or transgene and regulatory sequences that is to be expressed by the cell into which the plasmid is introduced. The term “recombinant” denotes a gene expression cassette that is not naturally occurring but has been engineered and may comprise different elements that do not occur together in nature or additional synthetic sequences. In this particular example, the recombinant gene expression cassette encodes a transgene comprising the coding sequence of a gene, an Fc domain and a hydroxyapatite binding domain. The recombinant gene expression cassette may further comprise enhancers, polyA sequences, linkers and further functional sequences or domains. The recombinant gene expression cassette may also comprise recognition or binding motifs, such as miRNA binding sites. The term “regulatory element” or “regulatory sequence” refers to non-coding nucleic acid sequences that control the transcription of genes or coding nucleic acid sequences. Regulatory elements include “enhancers” or “silencers”, which are recognized and bound by transcription factors, leading to upregulation ordownregulation of transcription, respectively. Regulatory elements also include “promoters”, which are nucleic acid sequences that include a transcription initiation site and transcription factor binding sites. Promoters are typically located directly upstream of a coding region and are operably linked to said coding region, meaning that they initiate transcription of this coding region. It is commonly recognized that the regulatory activity of promoters can differ depending on developmental timing and tissue specificity. In adult cells, tissues or organisms, the two main categories of promoters are tissue non-specific promoters and tissue-specific promoters. “Tissue non-specific promoters” are also called “constitutive” or “ubiquitous” promoters, meaning that they are always active, independent from the cell type or tissue or developmental timing. It is however conceivable that they are specifically engineered to be repressed in an experimental setting. Furthermore, their strength of expression is not necessarily equal in all cell types, and it is conceivable that in some cases exhibit less or no expression in a specific minority of cell types. “Tissue-specific promoters” or “regulated promoters” become active in the cell only in response to specific stimuli, for example specific transcription factors that are only present in one cell type or only in a small number of cell types. As used herein, the term “tissue-specific promoter” refers to a promoter that is predominantly active in a specific tissue in the adult organism. This does not exclude that the promoter is active, albeit to a lesser degree, in other cell types or tissues than the target tissue or in other developmental stages of the organism. Known tissue-specific promoters are functionally specific to the extent that they can be safely used for to target expression to a specific tissue in vivo. Such tissue-specific promoters are known, for example, for muscle tissue (e.g. desmin promoter, muscle creatine kinase (MCK) promoter), endothelial cells (e.g. angiopoietin-1 receptor (Tek / Tie2) promoter), neurons (e.g. synapsin 1 (Syn1) promoter), or liver (e.g. albumin (Alb) promoter, hybrid liver promoter (HLP), thyroxine binding globulin (TBG) promoter). Promoters can also be synthetic or engineered, non-naturally occurring sequences. For example, promoters can be designed to achieve higher levels of expression or to be regulated by elements of a specific cellular pathway or other synthetic factors. The term "polynucleotide" or “nucleic acid sequence” refers to a polymeric form of nucleotides of any length, including deoxyribonucleotides or ribonucleotides, or analogs thereof. A nucleic acid sequence is typically composed of a specific sequence of four nucleotide bases: adenine (A); cytosine (C); guanine (G); and thymine (T) (uracil (U) for thymine (T) when the nucleic acid sequence is RNA). Thus, the term polynucleotide sequence or nucleic acid sequence is the alphabetical representation of a polynucleotide molecule. A polynucleotide may comprise modified nucleotides, such as methylated or capped nucleotides and nucleotide analogs, and may be interrupted by non-nucleotide components. If present, modifications to the nucleotide structure may be imparted before or after assembly of the polymer. The term nucleic acid sequence, as used herein, refers interchangeably to double- and single-stranded polynucleotide molecules. Unless otherwise specified or required, any embodiment of the invention described herein that is a nucleic acid sequence encompasses both the double-stranded form and each of two complementary single-stranded forms known or predicted to make up the double-stranded form. The term “miRNA binding site” or “microRNA binding site” or “miRNA target” as used herein refers to a short nucleic acid sequence of typically about 5 to 30 nucleotides that comprises a sequence that is complementary to the sequence of a miRNA and to which a miRNA can bind. Upon binding of the miRNA to an mRNA comprising complementary binding sites, a double stranded RNA is formed which presents a target for cleavage and degradation by the cellular RNA interference (RNAi) pathway. Binding between miRNA and miRNA binding sites can be incomplete base-pairing or complete basepairing. As used herein, “isolated” refers to a nucleic acid molecule or a nucleic acid sequence that has been substantially separated, produced apart from, or purified away from other biological components in the cell or tissue of an organism in which the component occurs, such as other cells, chromosomal and extrachromosomal DNA and RNA, and proteins. Nucleic acids and proteins that have been “isolated” include nucleic acids and proteins purified by standard purification methods. The term also embraces nucleic acids and proteins prepared by recombinant expression in a host cell as well as chemically synthesized nucleic acids and proteins. Isolated proteins or nucleic acids, or cells containing such, in some examples are at least 50% pure, such as at least 75%, at least 80%, at least 90%, at least 95%, at least 98%, or at least 100% pure. "Host cells," "cell lines," "cell cultures," "packaging cell line" and other such terms denote higher eukaryotic cells, e.g., mammalian cells, such human cells, useful in the present invention. These cells can be used as recipients for recombinant vectors, viruses or other transfer polynucleotides, and include the progeny of the original cell that was transduced. It is understood that the progeny of a single cell may not necessarily be completely identical (in morphology or in genomic complement) to the original parent cell. The terms "polypeptide" and "protein" are used interchangeably herein to refer to polymers of amino acids of any length. The terms also encompass an amino acid polymer that has been modified; for example, disulfide bond formation, glycosylation, acetylation, phosphorylation, lipidation, or conjugation with a labeling component. The term “amino acid sequence” as used herein likewise refers to a continuous string of amino acids. This term can be used interchangeably with the terms “polypeptide” or “protein”. The term “amino acid sequence” may refer to a full-length protein, to a domain of a protein, to a functional region of a protein, or to a fragment or portion of a protein, wherein the fragment may be of any length. “Sequence identity” or “percentage identity” and “sequence similarity” can be determined by alignment of two peptide or two nucleotide sequences using global or local alignment algorithms. Sequences may then be referred to as “substantially identical” or “essentially similar” when they are optimally aligned. For example, sequence similarity or identity can be determined by searching against databases such as FASTA, BLAST, etc., but hits should be retrieved and aligned pairwise to compare sequence identity. Two proteins or two protein domains, or two nucleic acid sequences can have “substantial sequence identity” if the percentage sequence identity is at least 70%, 75%, 80%, 85%, 90%, 95%, 98%, 99% or more, preferably 90%, 95%, 98%, 99% or more. Such sequences are also referred to as “variants” herein, e.g., other variants of a missing, deficient, and / or mutant protein or enzyme. I Alternatively, the degree of sequence similarity between polynucleotides can be determined by hybridization of polynucleotides under conditions that form stable duplexes between homologous regions, followed by digestion with single-stranded-specific nuclease(s), and size determination of the digested fragments. Two DNA, or two polypeptide sequences are "substantially homologous" to each other when the sequences exhibit at least about 80-85%, preferably 85-90%, more preferably 90-95%, and most preferably 98-100% sequence identity to the reference sequence over a defined length of the molecules, as determined using the methods above. As used herein, substantially homologous also refers to sequences showing complete identity to the specified DNA or polypeptide sequence. DNA sequences that are substantially homologous can be identified in a Southern hybridization experiment under, for example, stringent conditions, as defined for that particular system. Defining appropriate hybridization conditions is within the skill of the art. The term “composition” as used herein refers to a mixture comprising a therapeutically effective amount of the agent according to the present invention, i.e. a viral plasmid or recombinant virus of the invention, and one or more excipients. The term “excipient” as used herein may also be referred to as “pharmaceutically acceptable carrier”, or “pharmaceutically acceptable excipient,” “pharmaceutically acceptable diluent,”, or “pharmaceutically acceptable vehicle,” used interchangeably herein, refer to a non-toxic solid, semisolid or liquid filler, diluent, encapsulating material or formulation auxiliary of any conventional type. A pharmaceutically acceptable carrier is essentially non-toxic to recipients at the dosages and concentrations employed and is compatible with other ingredients of the formulation. A pharmaceutically acceptable carrier will not inhibit otherwise adversely 25 affect the function of the agent according to the present invention. Suitable carriers include, but are not limited to water, dextrose, glycerol, saline, ethanol, and any combination thereof. The carrier can contain additional agents such as wetting or emulsifying agents, pH buffering agents, or adjuvants, which enhance the effectiveness of the formulation. As used herein, the term “excipient” refers to an inert substance which is commonly used as a diluent, vehicle, preservative, binder, or stabilizing agent, and includes, but is not limited to, proteins (e.g., serum albumin, etc.), amino acids (e.g., aspartic acid, glutamic acid, lysine, arginine, glycine, histidine, etc.), fatty acids and phospholipids (e.g., alkyl sulfonates, caprylate, etc.), surfactants (e.g., SDS, polysorbate, nonionic surfactant, etc.), saccharides (e.g., sucrose, maltose, trehalose, etc.) and polyols (e.g., mannitol, sorbitol, etc.). The term "bone tissue" is used herein to refer to tissue synthesized by osteoblasts, composed of an organic matrix containing mostly collagen and mineralized by the deposition of hydroxyapatite crystals. Hydroxyapatite makes up about 60% of the inorganic bone material and is also referred as “bone mineral”. The words “treat” or “treating” or “treatment” include palliative treatment, that is, treatment designed for the relief of symptoms rather than the curing of the disease, pathological condition, or disorder; preventative treatment, that is, treatment directed to minimizing or partially or completely inhibiting the development of the associated disease, pathological condition, or disorder; and supportive treatment, that is, treatment employed to supplement another specific therapy directed toward the improvement of the associated disease, pathological condition, or disorder. In an aspect, the terms cover any treatment of a subject, including a mammal (e.g., a human), and includes: (i) preventing the undesired physiological change, disease, pathological condition, or disorder from occurring in a subject that can be predisposed to the disease but has not yet been diagnosed as having it; (ii) inhibiting the physiological change, disease, pathological condition, or disorder, i.e., arresting its development; or (iii) relieving the physiological change, disease, pathological condition, or disorder, i.e., causing regression of the disease. For example, in an aspect, treating a disease or disorder can reduce the seventy of an established a disease or disorder in a subject by 1 %-100% as compared to a control. In an aspect, treating can refer to a 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, or 100% reduction in the seventy of a disease or disorder (such as a genetic disease or disorder). For example, treating a disease or disorder can reduce one or more symptoms of a disease or disorder in a subject by 1 %-I 00% as compared to a control. In an aspect, treating can refer to 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, 100% reduction of one or more symptoms of an established a disease or disorder. It is understood that treatment does not necessarily refer to a cure or complete ablation or eradication of a disease or disorder. However, in an aspect, treatment can refer to a cure or complete ablation or eradication of a disease or disorder. An "individual" or "subject" treated in accordance with this invention refers to vertebrates, particularly members of a mammalian species, and includes but is not limited to domestic animals, sports animals, and primates, including humans. In one embodiment, the subject treated in accordance with this invention is a mammal. In one embodiment, the subject treated in accordance with this invention is a human. In another embodiment, the subject treated in accordance with this invention is a nonhuman mammal. “Wild-type”, “control” or “reference” gene expression, mRNA or protein levels are determined by a control sample, cell or organisms, or by averaging the expression levels from multiple control samples, cells or organisms. In the context of the present invention, the term “wild-type” or "control" refers to a cell or organism that is healthy or a sample from a subject that is healthy or to a cell or organism with a specific disease that is different from the disease to be treated. The term “genetic disease” or “genetic disorder” as used herein refers to a disease caused by one or more mutations in a single gene (monogenic) or in multiple genes (polygenic). The genetic disease may be autosomal dominant, autosomal recessive, X-linked dominant, X-linked recessive, Y-linked or mitochondrial. The term “gene therapy” as used herein refers to the alteration of endogenous gene expression by introduction of a therapeutic agent. Most commonly, gene therapy involves the introduction of foreign, i.e. heterologous, DNA or RNA into a cell or organism. This results in an increase or decrease of gene expression or in the replacement of a defective gene. The introduction of a heterologous nucleic acid can be achieved with a vector, such as a Parvoviridae vector comprising the viral plasmid of the invention. The term “pyrophosphate deposition disease” refers to a group of diseases which is characterized by elevated blood or urine levels of three phosphocompounds: pyridoxal 5'-phosphate (PLP), inorganic pyrophosphate (PPi), and phosphoethanolamine (PEA). This is due to subnormal alkaline phosphatase activity in serum. A high ratio of inorganic pyrophosphate (PPi) to phosphate ions (Pi) can result in the deposition of calcium pyrophosphate crystals (CPP). CPP crystal depositions in joints lead to an inflammatory response and symptoms of arthritis, a condition referred to as calcium pyrophosphate deposition disease (CPDD). Additionally, PPi is a potent mineralization inhibitor, in which Pi is incorporated into bone mineral (hydroxyapatite). Hence, an abnormally increased ratio of PPi to Pi results in under-mineralized bone tissues. This symptom is a hallmark of hypophosphatasia (HPP), a genetic disorder caused by a mutation in the gene encoding tissue-nonspecific alkaline phosphatase (TNAP, gene name ALPL). Another symptom of HPP are vitamin B6-dependent seizures, caused by accumulation of PLP, a co-factor form of vitamin B6. The abbreviations “TNAP”, “TNSALP”, and “TNALP” are used interchangeably and refer to the protein “tissue non-specific alkaline phosphatase” expressed from the gene ALPL (Human Genome Organisation Gene Nomenclature Committee (HGNC) accession number 438, National Center for Biotechnology Information (NCBI) gene number 249). TNAP is a membrane-bound protein anchored through a glycolipid anchor (GPI). The GPI anchor is added post translationally after removal of a hydrophobic C-terminal end which serves both as a temporary membrane anchor and as a signal for the addition of the GPI. Hence the soluble human TNAP (sTNAP) used in all Examples below is comprised of a TNALP wherein the first amino acid of the hydrophobic C-terminal sequence, namely alanine, is either replaced by a stop codon or by a codon that functions as part of a new fused peptide sequence. The soluble TNAP so formed contains all amino acids of the native anchored form of TNAP necessary for the formation of the catalytic site but lacks the GPI membrane anchor. Viral Plasmids and Recombinant Gene Expression Cassette Regulatory Element In one embodiment, the regulatory element of b) comprises one or more promoters. In one embodiment, the regulatory element of b) further comprises one or more enhancer. Hence, in one embodiment, the regulatory element of b) comprises one or more promoters and one or more enhancers. In another embodiment, the regulatory element of b) comprises no enhancers. In one embodiment, the regulatory element of b) is a tissue-specific promoter. The tissue-specific promoter may be a naturally occurring promoter or a non-naturally occurring, engineered or synthetic promoter. In one embodiment, the tissue-specific promoter is an engineered promoter. In one embodiment, the tissue-specific promoter is a synthetic promoter. In another embodiment, the tissue-specific promoter is a hybrid promoter. Conversely, in one embodiment, the regulatory element of b) is not a tissue non-specific promoter. A tissue non-specific promoter is a constitutively active promoter. Tissue non-specific promoters are usually derived from the regulatory regions of constitutively active genes, so-called housekeeping genes. Examples of tissue non-specific promoters include CAG (CMV early enhancer / chicken p-Actin), CBA (chicken p-Actin), CMV (Cytomegalovirus promoter), HBA (human p-Actin), UBC (Ubiquitin C promoter), EF1a (elongation factor 1a promoter), PGK (phosphoglycerate kinase promoter), or SV40 (simian virus 40 promoter). Hence, in one embodiment, the regulatory element of b) is not a promoter selected from the group consisting of CAG, CBA, CMV, HBA, UBC, EF1a, PGK and SV40. In a particular embodiment, the regulatory element of b) is not a promoter selected from the group consisting of CAG, CBA and CMV. Preferably, the regulatory element of b) is not CAG. Hence, in a particular embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue-specific promoter operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In another embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue-specific promoter operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR 126-3p or miR126-5p; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one embodiment, the regulatory element of b) is a tissue specific promoter, wherein the tissue specific promoter is a liver-specific promoter. Exemplary liver-specific promoters are HLP (hybrid liver-specific promoter, described in Sandig et al. (1996) Gene Ther 3(11):1002-1009), hAAT (human a-antitrypsin), Alb (Albumin), HBV (hepatotrophic hepatitis B virus), HCB (synthetic promoter, described in Brown et al. (2018) Mol Ther Methods Clin Dev 9:57-69), LP1 (liver-restricted mini-human factor IX expression cassette, described in Nathwani et al. (2006) Blood 107 (7):2653-2661), LP1b (liver-specific promoter LP1b was engineered by combining elements from the human apolipoprotein E / C-l gene locus control region (ApoE-HCR) and a modified human a1 antitrypsin promoter (hAAT), described in Agudelo et al. (2020) Genome Research 30(1):107-117), TTR (transthyretin promoter, described in Yan et al. (1990) EMBO J 9:869-878). Hence, in one embodiment, the liver-specific promoter is selected from the group consisting of HLP, hAAT, Alb, HBV, HCB, LP1, LP1b, and TTR. In a preferred embodiment, the liver-specific promoter is HLP or HCB. Hence, in a particular embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In another embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. sTNAP In order to reduce off-target effects, the inventors produced a codon-optimized nucleic acid sequence of sTNAP that is optimized for liver expression. In one embodiment, the polynucleotide a) comprises a nucleic acid sequence that is at least 70% identical to the nucleic acid sequence set forth in SEQ ID NO: 1. In another embodiment, the polynucleotide a) comprises a nucleic acid sequence that is at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid sequence set forth in SEQ ID NO: 1. In a preferred embodiment, the polynucleotide a) comprises a nucleic acid sequence that is 80% identical to the nucleic acid sequence set forth in SEQ ID NO: 1. In one embodiment, the polynucleotide a) encodes an amino acid sequence that is at least 70% identical to the amino acid sequence set forth in SEQ ID NO. 2. In another embodiment, the polynucleotide a) encodes an amino acid sequence that is at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the amino acid sequence set forth in SEQ ID NO: 2. Fc domain In one embodiment, the invention provides a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); and c) a polynucleotide encoding a stabilizing domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one embodiment, the stabilizing domain extends the half-life of sTNAP. In one embodiment, the stabilizing domain is an FcRn (neonatal Fc receptor) interacting protein domain. In a particular embodiment, the stabilizing domain is selected from an Fc fragment of a mammalian IgG, IgA or IgD antibody and albumin. In one embodiment, the Fc domain of c) comprises the amino acid sequence of an Fc domain from a mammalian IgG, IgA or IgD antibody. Useful Fc fragments for the present invention include Fc fragments of IgG that comprise the hinge, and the CH2 and CH3 domains. lgG-1, lgG-2, lgG-3, lgG-3 and lgG-4for instance can be used. Preferably, the Fc domain of c) comprises the amino acid sequence of an Fc domain from a human IgG antibody. In one embodiment, the Fc domain of c) comprises the hinge, CH2 and CH3 domains from a human IgG antibody. In one embodiment, the Fc domain of c) comprises a nucleic acid sequence that is at least 70% identical to the nucleic acid sequence of SEQ ID NO: 5. In another embodiment, the Fc domain of c) comprises a nucleic acid sequence that is at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid set forth in SEQ ID NO: 5. In one embodiment, the Fc domain of c) encodes an amino acid that is at least 70% identical to the amino acid sequence set forth in SEQ ID NO: 6. In another embodiment, the Fc domain of c) encodes an amino acid sequence that is at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the amino acid set forth in SEQ ID NO: 6. Hydroxyapatite Binding Domain In one embodiment, the hydroxyapatite binding domain of d) comprises poly-aspartic acid (D) or poly-glutamic acid (E), or any combination of D and E. In one embodiment, the hydroxyapatite binding domain of d) is poly-aspartic acid (D) or poly-glutamic acid (E). In one embodiment, the hydroxyapatite binding domain of d) comprises at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, or at least 15 continuous residues. In one embodiment, the hydroxyapatite binding domain of d) comprises at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, or at least 15 continuous acidic amino acid residues. In one embodiment, the hydroxyapatite binding domain of d) comprises at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, or at least 15 continuous acidic amino acid residues consisting of either D or E or any combination of D and E. In one embodiment, the hydroxyapatite binding domain of d) is a poly aspartic acid comprising between six and fifteen continuous residues, i.e. D6 to D15. In one embodiment, the hydroxyapatite binding domain of d) comprises at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, or at least 15 continuous aspartic acid residues. In a particular embodiment, the hydroxyapatite binding domain of d) is decapeptide aspartic acid, i.e. D10. Hence, in a particular embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d)    a polynucleotide encoding a poly-aspartic acid domain, preferably a D10 domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In another embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a poly-aspartic acid domain, preferably a D10 domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. ITRs The at least one ITR can be from a wild-type virus variant, a non-naturally occurring virus variant, a synthetic virus variant or an engineered virus variant of a virus from the family Parvoviridae. In one embodiment, the at least one ITR is from a virus of a genus selected from the group consisting of amdoparvovirus, aveparvovirus, bocaparvovirus, copiparvovirus, dependoparvovirus, erythroparvovirus, and tetraparvovirus. In a preferred embodiment, the at least one ITR is from a virus of the genus dependoparvovirus. In an even more preferred embodiment, the at least one ITR is from an adeno-associated virus (AAV). In one embodiment, the at least one ITR is from an AAV selected from the group consisting of AAV1, AAV2, AAV3, AAV4, AAV5, AAV6, AAV7, AAV8, AAV9, AAV10, AAV11, AAV12, AAV13. In another embodiment, the at least one ITR is from AAV2. In a preferred embodiment, the at least one ITR is two paired ITRs flanking the recombinant gene expression cassette, a 5’ ITR and a 3’ ITR. In one embodiment, the nucleic acid sequences of the paired ITRs flanking the recombinant gene expression cassette are reverse-complement. In one embodiment, the nucleic acid sequence of the 5’ ITR is at least 80% identical to the nucleic acid sequence set forth in SEQ ID NO: 7 and the nucleic acid sequence of the 3’ ITR is at least 80% identical to the nucleic acid sequence set forth in SEQ ID NO: 8. In one embodiment, the nucleic acid sequence of the 5’ ITR is at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99%, at least 99.5% or 100% identical to the nucleic acid sequence set forth in SEQ ID NO: 7 and the nucleic acid sequence of the 3’ ITR is at least 85%, at least 90%, at least 95%, at least 97%, at least 98%, at least 99%, at least 99.5% or 100%identical to the nucleic acid sequence set forth in SEQ ID NO: 8. Hence, in one embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the expression level of the recombinant gene expression cassette in liver and / or bone cells is higher relative to the expression of the recombinant gene expression cassette in vasculature cells when determined by quantitative PCR; and wherein the recombinant expression cassette is flanked by ITRs from AAV2. Hence, in one embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a); d) a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the expression level of the recombinant gene expression cassette in liver and / or bone cells is higher relative to the expression of the recombinant gene expression cassette in vasculature cells when determined by quantitative PCR; and wherein the recombinant expression cassette is flanked by ITRs from AAV2. miRNA Binding Site The recombinant gene expression cassette may further comprise one or more miRNA binding sites. Specifically, the miRNA binding site is recognized by an endogenously occurring miRNA. In one embodiment, the miRNA binding site is recognized by an endogenously occurring miRNA that has a tissue specific expression pattern. This means that the miRNA is highly expressed in some tissue and has no or very little expression in other tissues. In one embodiment, the miRNA binding site is recognized by an endogenously occurring miRNA that is highly expressed in cells of the vasculature. In one embodiment, the miRNA binding site is recognized by an endogenously occurring miRNA that is highly expressed in vascular and microvascular endothelial cells and in vascular smooth muscle cells. In one embodiment, the miRNA binding site is recognized by an endogenously occurring miRNA that is highly expressed in HUVEC (Human umbilical vein endothelial cells), HCAEC (Human Coronary Artery Endothelial Cells), HAoEC (Human Aortic Endothelial Cells), HCMEC (Human Cerebral Endothelial Cells), HCASMC (Human Coronary Artery Smooth Muscle Cells) and HAoSMC (Human Aortic Smooth Muscle Cells) cells. In one particular embodiment, the miRNA binding site is recognized by an endogenously occurring miRNA that is highly expressed in vasculature cells and has little or no expression in liver and / or bone cells. In one embodiment, miRNA has little or no expression in HepG2 (human liver cancer cell line), Huh-7 (human hepatocyte-derived carcinoma cell line), hF0B1.19 (human fetal osteoblast cell line) and U2OS (human osteosarcoma cell line) cells. In this context, “little or no expression” means that the expression level of the miRNA in liver and / or bone cells is lower relative to the expression of the miRNA in endothelial and smooth muscle cells of the vasculature when determined by quantitative PCR. In one embodiment, the expression level of the miRNA is higher in endothelial and smooth muscle cells of the vasculature than in liver and / or bone cells. The skilled person is aware of techniques that are useful in determining the expression level of miRNAs. In one embodiment, the expression level of the miRNA is determined by qPCR or nucleic acid probe hybridization. In one embodiment, the Ct (threshold cycle) of miRNA-specific qPCR probes is higher in vasculature cells than in liver and / or bone cells. Hence, in one embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the expression level of the recombinant gene expression cassette in liver and / or bone cells is higher relative to the expression of the recombinant gene expression cassette in vasculature cells when determined by quantitative PCR; and wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. Since the one or more miRNA binding sites regulate tissue-specific expression of the transgene, a tissue non-specific promoter may be used in a construct comprising miRNA binding sites. Hence, in one embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue non-specific promoter operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the expression level of the recombinant gene expression cassette in liver and / or bone cells is higher relative to the expression of the recombinant gene expression cassette in vasculature cells when determined by quantitative PCR; and wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one particular embodiment, the one or more miRNA binding sites are recognised by miR126. In one embodiment, the one or more miRNA binding sites are recognised by miR126-3p and / or miR126-5p. Preferably, the one or more miRNA binding sites are recognised by miR126-5p. In one embodiment, the one or more miRNA binding sites comprise a nucleic acid sequence at least 70% identical to the nucleic acid sequence as set forth in SEQ ID NO: 9. In another embodiment, the one or more miRNA binding sites comprise a nucleic acid sequence that is at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid set forth in SEQ ID NO: 9. In one embodiment, the one or more miRNA binding sites comprise at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 or at least 8 miRNA binding site, wherein each of the binding sites comprises the nucleic acid sequence set forth in SEQ ID NO: 9. Hence, in one particular embodiment, the invention relates to a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one embodiment, the recombinant gene expression cassette comprises between 1 and 8 miRNA binding sites. In one embodiment, the recombinant gene expression cassette comprises at least 1 miRNA binding site. In one embodiment, the recombinant gene expression cassette comprises at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 or at least 8 miRNA binding site. In a preferred embodiment, the recombinant gene expression cassette comprises 2 or 4 miRNA binding sites. In an even more preferred embodiment, the recombinant gene expression cassette comprises 2 miRNA binding sites. In one embodiment, the one or more miRNA binding sites comprise at least two binding sites and comprises a nucleic acid sequence at least 70% identical to the nucleic acid sequence as set forth in SEQ ID NO: 10. In another embodiment, the one or more miRNA binding sites comprise at least two binding sites and comprises by a nucleic acid sequence that is at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid set forth in SEQ ID NO: 10. In another embodiment, the recombinant gene expression cassette of the viral plasmid further comprises a polynucleotide comprising one or more 5’ intron sequences. In another embodiment, the recombinant gene expression cassette of the viral plasmid further comprises a polynucleotide comprising one or more Woodchuck Hepatitis Virus posttranscriptional regulatory element (WPRE) sequences. In one embodiment, WPRE sequences enhance transgene expression compared to transgenes not comprising a WPRE element. In one embodiment, WPRE sequences enhance transgene expression compared to transgenes not comprising a WPRE element when measured by either qPCR, Western Blot, nucleic acid probe hybridisation, ELISA or antibody hybridisation. A further aspect of the invention relates to the use of miRNA binding sites for targeted transgene expression in liver and bone tissue while suppressing expression in endothelial tissue. In one embodiment, the invention provides a miRNA binding site that regulates the expression of a transgene, wherein the expression is downregulated in vascular cells 43 and the expression is not downregulated or relatively less downregulated in liver cells and bone cells. In one embodiment, the invention provides a miRNA binding site that regulates the expression of a transgene, wherein the expression level of the transgene in liver and / or bone cells is higher relative to the expression of the transgene in vasculature cells when determined by quantitative PCR. In another embodiment, the invention relates to the use of miRNA binding sites for targeted transgene expression in the liver, wherein the miRNA binding sites are recognised by a miR-126 and wherein the transgene expression is downregulated in vascular cells and the transgene expression is not downregulated in liver cells and bone cells. In another embodiment, the invention relates to the use of miRNA binding sites for targeted transgene expression in the liver, wherein the miRNA binding sites are recognised by a miR126-3p or miR-126-5p and wherein the expression is downregulated in vascular cells and the expression is not downregulated in liver cells and bone cells. In another embodiment, the invention relates to the use of miRNA binding sites for targeted transgene expression in the liver, wherein the miRNA binding sites are recognised by a miR-126-5p and wherein the expression is downregulated in vascular cells and the expression is not downregulated in liver cells and bone cells, wherein the miRNA binding sites comprise the nucleic acid sequence set forth in SEQ ID NO: 9. Plasmid and Transqene In one embodiment, the expression product of the recombinant gene expression cassette is a fusion protein comprising in order from N-terminal to C-terminal the sTNAP, the Fc domain and the hydroxyapatite binding domain. The regulatory element may be located upstream of the fusion protein. Hence, in one embodiment, the recombinant gene expression cassette comprises polynucleotides elements arranged in the order of regulatory element, sTNAP, and hydroxyapatite binding domain. In one embodiment, the recombinant gene expression cassette comprises polynucleotides elements arranged in the order of regulatory element, sTNAP, Fc domain, and hydroxyapatite binding domain. Hence, in one embodiment, the recombinant gene expression cassette comprises polynucleotides elements arranged in the order of regulatory element, sTNAP, Fc domain, hydroxyapatite binding domain, and one or more miRNA binding site. In one embodiment, the viral plasmid comprises polynucleotide elements arranged in the order of 5’ITR, regulatory element, sTNAP, Fc domain, hydroxyapatite binding domain, one or more miRNA binding site, 3’ITR. In one embodiment, the viral plasmid comprises the polynucleotides arranged in the order of 5’ITR, liver-specific promoter, sTNAP, Fc domain, D10 domain, two or more miRNA binding sites, 3’ITR. In another embodiment, the viral plasmid comprises the polynucleotides arranged in the order of 5’ITR, liver-specific promoter, sTNAP, D10 domain, Fc domain, two or more miRNA binding sites, 3’ITR. In one embodiment, the invention provides a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: - a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; - a polynucleotide encoding a regulatory element operatively linked to the polynucleotide encoding sTNAP; and -     a polynucleotide encoding a stabilizing domain; and -     a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one embodiment, the invention provides a viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: - a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; - a polynucleotide encoding a regulatory element operatively linked to the polynucleotide encoding sTNAP; and -     a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and -     a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. In one embodiment, the expression product of the recombinant gene expression cassette is a fusion protein encoded by a nucleic acid sequence at least 70% identical to the nucleic acid sequence set forth in SEQ ID NO: 11. In one embodiment, the fusion protein is encoded by a nucleic acid sequence at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% % identical to the nucleic acid set forth in SEQ ID NO: 11 The fusion protein is also referred to as transgene herein. In one embodiment, the expression product of the recombinant gene expression cassette is a fusion protein comprising an amino acid sequence at least 70% identical to the amino acid sequence set forth in SEQ ID NO: 12. In one embodiment, the fusion protein comprises an amino acid sequence at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% % identical to the amino acid set forth in SEQ ID NO: 12. The fusion protein is also referred to as transgene. In another aspect, the invention also relates to an isolated polynucleotide comprising the recombinant gene expression cassette of the invention. In one embodiment, the isolated polynucleotide comprises a nucleic acid sequence at least 70% identical to the nucleic acid sequence set forth in SEQ ID NO: 13. In another embodiment, the isolated polynucleotide comprises a nucleic acid sequence that is at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid set forth in SEQ ID NO: 13. In another aspect, the invention also relates to an isolated polynucleotide comprising the viral plasmid of the invention. In one embodiment, the isolated polynucleotide comprises a nucleic acid sequence at least 70% identical to the nucleic acid sequence set forth in SEQ ID NO: 14. In another embodiment, the isolated polynucleotide comprises a nucleic acid sequence that is at least 75%, at least 80%, at least 85, at least 90%, at least 95%, at least 98%, at least 99% or 100% identical to the nucleic acid set forth in SEQ ID NO: 14. In one embodiment, the recombinant gene expression cassette further comprises linkers. Non-viral gene therapy uses It is understood that plasmids can be used in gene therapy without the need to vectorize i.e. to produce a virus. Plasmid DNA can be a component of non-viral gene therapy. For example, the plasmid of the invention may be administered with lipid formulations compatible with gene therapy or lipid nanoparticles either ex-vivo or in-vivo. Such gene therapy lipids or lipid nanoparticles exhibit inherent liver tropism. Alternatively, plasmid DNA can be used as naked DNA and administered via Hydrodynamic Delivery. Hence, in one embodiment, the invention also provides a plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain. In one embodiment, the invention also provides a plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; for use in gene therapy. In one embodiment, the invention also provides a plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; for use in the treatment of pyrophosphate deposition diseases. In one embodiment, the invention also provides a plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; for use in the treatment of pyrophosphate deposition diseases. In a preferred embodiment, the pyrophosphate deposition disease is hypophosphatasia (HPP). In one embodiment, the plasmid is administered using gene therapy lipids or lipid nanoparticles. In one embodiment, the gene therapy lipids or lipid nanoparticles exhibit liver tropism. It is understood that the gene expression cassette of the invention is also suitable for inclusion into other DNA vehicles than plasmids, such as, for example, cosmids or bacterial artificial chromosomes (BACs) or other isolated nucleic acids. In addition, the gene expression cassette may also be comprised in a linear isolated DNA fragment. Hence, in one embodiment, the invention also provides a recombinant gene expression cassette, comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain. In another embodiment, the invention also provides a recombinant gene expression cassette, comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; for use in the treatment of pyrophosphate deposition diseases. Recombinant Virus The recombinant virus is characterized by comprising a viral genome, i.e. a recombinant gene expression cassette, or transgene, flanked by ITRs, and a capsid. The capsid is composed of viral proteins (VP), including VP1, VP2 and VP3. The viral proteins are encoded by a cap gene. The virus species or serotype of the capsid refers to the virus species or serotype the cap gene, i.e. the viral proteins, originate from. The capsid can be from a wild-type virus variant, a non-naturally occurring virus variant, a synthetic virus variant or an engineered virus variant of a virus from the family Parvoviridae. In one embodiment, the capsid is from a virus of a genus selected from the group consisting of amdoparvovirus, aveparvovirus, bocaparvovirus, copiparvovirus, dependoparvovirus, erythroparvovirus, and tetraparvovirus. In a preferred embodiment, the capsid is from a virus of the genus dependoparvovirus. In an even more preferred embodiment, capsid is from an adeno-associated virus (AAV). Preferably, the capsid is from an AAV exhibiting liver tropism. In one embodiment, the capsid is from a natural AAV serotype capable of transducing liver and / or bone cells, or the capsid is an artificially designed AAV capsid capable of transducing liver and / or bone cells. Examples of natural AAV serotypes capable of transducing liver and / or bone cells are AAV8 and AAV9. Examples of artificially designed AAV capsids capable of transducing liver and / or bone cells are LK03 (described by Lisowski et al. (2014) Nature 506:382-386) and NP40 (described by Paulk et al. (2018), Mol Ther 26:289-303). Hence, in one embodiment, the capsid is selected from the group consisting of AAV8, AAV9, KL03 and NP40. In a preferred embodiment, the capsid is from AAV8. Hence, in a particular embodiment, the capsid is selected from the group consisting of AAV8, AAV9, KL03 and NP40 and the recombinant gene expression cassette is flanked by two ITRs of AAV2. Hence, in a particular embodiment, the capsid is from AAV8 and the recombinant gene expression cassette is flanked by two ITRs of AAV2. In another embodiment, the capsid is from AAV9 and the recombinant gene expression cassette is flanked by two ITRs of AAV2. Hence, in a particular embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue-specific promoter operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the recombinant expression cassette is flanked by ITRs from AAV2. Hence, in a particular embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue-specific promoter operatively linked to the polynucleotide of a); c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the recombinant expression cassette is flanked by ITRs from AAV6. In another embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a tissue-specific promoter operatively linked to the polynucleotide of a); c) a polynucleotide encoding an Fc domain; d) a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the recombinant expression cassette is flanked by ITRs from AAV2. Hence, in a particular embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a), preferably HLP; c) a polynucleotide encoding a stabilizing domain, preferably an Fc domain; and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the recombinant expression cassette is flanked by ITRs from AAV2. In another embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a), preferably HLP; c)    a polynucleotide encoding a stabilizing domain, preferably an Fc domain; d)    a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the recombinant expression cassette is flanked by ITRs from AAV2. In another embodiment, the invention relates to a recombinant AAV8 comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a liver-specific promoter operatively linked to the polynucleotide of a), preferably HLP; d) a polynucleotide encoding a hydroxyapatite binding domain; and e) a polynucleotide encoding one or more miRNA binding sites, preferably wherein the miRNA binding sites are recognized by miR126-3p or miR126-5p; wherein the expression level of the recombinant gene expression cassette in liver and / or bone cells is higher relative to the expression of the recombinant gene expression cassette in vasculature cells when determined by quantitative PCR; and wherein the recombinant expression cassette is flanked by ITRs from AAV2. In another aspect, the invention also relates to a host cell comprising the viral plasmid, the isolated polynucleotide or the recombinant virus of the invention. A host cell can be any mammalian cell capable of being transduced with the viral plasmid and helper plasmids and producing the virus. The skilled person is familiar with suitable host cells, such as HEK293 cells or CHO cells. Medical Uses In a further aspect, the invention also relates to a pharmaceutical composition comprising the viral plasmid, the isolated polynucleotide, the recombinant virus or the host cell of the invention, and optionally one or more excipients. Gene therapy can be conducted to enhance the level of expression of TNAP. A recombinant virus comprising the recombinant gene expression cassette of the invention may be used to genetically alter cells either for TNAP marking, replacement of a missing or defective TNAP, or insertion of a therapeutic TNAP. The introduction of a recombinant virus comprising the recombinant gene expression cassette of the invention may involve use of any number of delivery techniques (both surgical and non-surgical) which are available and well known in the art. Such delivery techniques, for example, include vascular catheterization, cannulization, injection, inhalation, endotracheal, subcutaneous, inunction, topical, oral, percutaneous, intraarterial, intravenous, and / or intraperitoneal administrations. In particular, for delivery of a virus comprising the viral plasmid of the invention to a tissue, any physical or biological method that will introduce the virus comprising the viral plasmid of the invention to a host cell or organism can be employed. In a preferred embodiment, the recombinant virus of the invention is administered intravenously. Compositions of this invention may be used in vivo as well as ex vivo. In vivo gene therapy comprises administering the virus comprising the viral plasmid of the invention directly to a subject. Pharmaceutical compositions can be supplied as liquid solutions or suspensions, as emulsions, or as solid forms suitable for dissolution or suspension in liquid prior to use. For administration into the respiratory tract, one mode of administration is by aerosol, using a composition that provides either a solid or liquid aerosol when used with an appropriate aerosolubilizer device. Another mode of administration into the respiratory tract is using a flexible fiberoptic bronchoscope to instill the vectors. Typically, the viral vectors are in a pharmaceutically suitable pyrogen-free buffer such as Ringer's balanced salt solution (pH 7.4). Although not required, pharmaceutical compositions may optionally be supplied in unit dosage form suitable for administration of a precise amount. The decision of whether to use in vivo or ex vivo therapy, and the selection of a particular composition, dose, and route of administration will depend on a number of different factors, including but not limited to features of the condition and the subject being treated. The assessment of such features and the design of an appropriate therapeutic or prophylactic regimen is ultimately the responsibility of the prescribing physician. One objective of the invention is to provide an improved treatment for pyrophosphate deposition diseases. Hence, the invention provides a plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for use as a medicament. The invention also provides the use of a viral plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for the manufacture of a medicament. The invention also provides a method of treatment comprising the administration of an effective amount of the viral plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention to a subject in need thereof. Thus, the invention provides a method of treatment of pyrophosphate deposition diseases comprising the administration of an effective amount of the viral plasmid of the invention to a subject in need thereof. Another aspect of the invention relates to a plasmid of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention for use in the treatment of pyrophosphate deposition diseases in a subject in need thereof. In one embodiment, the treatment is administered once. Particularly, in one embodiment, the treatment is administered once and the therapeutic effect remains stable over an extended period of time, preferably over the subject’s lifetime. In one embodiment, the treatment increases mineralization in bone and / or dental tissue in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. In one embodiment, the treatment increases mineralization in bone tissue in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases, as measured by X-ray imaging. In another embodiment, the treatment increases the ratio of extracellular Pi to PPi in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. In a preferred embodiment, the pyrophosphate deposition disease is hypophosphatasia (HPP). In one embodiment, the treatment improves one or more of the symptoms of HPP selected from the group consisting of neurological symptoms such as depression, brain fog, epilepsy, fatigue, and migraine; musculoskeletal symptoms such as myalgia, arthralgia, muscle weakness, stress fractures, delayed bone healing, rickets, osteomalacia, chondrocalcinosis, tendinosis calcarea, and bone marrow edema; dental symptoms such as hypomineralized teeth and early loss of primary and permanent teeth; and gastric and renal symptoms such as nausea, digestive irritation, nephrocalcinosis and kidney stones. In one embodiment, the treatment reduces the need for ventilatory support in a subject suffering from HPP. In one embodiment, the treatment reduces the frequency of occurance of bone fractures in a subject suffering from HPP compared to the baseline frequency before treatment. In mice, the preferred dose of recombinant virus is between 1 x 1012 vg / kg to 8 x 1013 vg / kg. The dose of about 1 x 1012 vg / kg is referred to as a low dose. The low dose may be between 1x 1012 and 3 x 1012 vg / kg in mice. The high dose may be between 1 x 1013 and 8 x 1013 vg / kg in mice. In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a maximum dose of about 2 x 1012 to about 2 x 1014 vg / kg (vector genomes per kg). In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a maximum dose of about 2 x 1012 to about 2 x 1014 vg / kg, wherein the recombinant virus comprises an AAV8 capsid.In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a dose of 1 x 1013 to 3 x 1013 vg / kg (vector genomes per kg). In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a maximum dose of 2 x 1012, 5 x 1012, 1 x 1013, 2 x 1013 or 3 x 1013 vg / kg. In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a maximum dose of 1 x 1013, 1.5 x 1013, 2 x 1013, 2.5 x 1013, or 3 x 1013 vg / kg. It is understood that in some circumstances, for example dose finding studies or clinical trials, the recombinant virus will be administered in higher doses. Hence, the recombinant virus for use according to the invention may be administered to a human subject in need thereof at a dose of 1 x 1014 or more. In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a dose of less than 2 x 1012. In one embodiment, the recombinant virus for use according to the invention is administered to a human subject in need thereof at a dose of less than 2 x 1012, wherein the recombinant virus exhibits an improved liver tropism compared to AAV8. In one embodiment, the recombinant virus for use according to the invention is administered to a subject who has previously received enzyme replacement therapy (ERT) for hypophosphatasia. The ERT doses may be administered 7 days a week (consecutive), 6 or less days a week (consecutive and non-consecutive), 5 or less days a week, 4 or less days a week, 3 or less days a week, 2 or less days a week, or once a week. For example, the ERT may be administered 3 times a week on non-consecutive days. In one embodiment, ERT is administered at a total of 6 mg / kg / week subcutaneously or in some cases 9 mg / kg / week. In one embodiment, ERT is administered as 2 mg / kg given 3 x / week or 1 mg / kg given 6 x / week, or in some cases 3 mg / kg 3 x / week. In one embodiment, the recombinant virus for use according to the invention is administered to a subject who has previously received at least 10 doses of enzyme replacement therapy for hypophosphatasia. In another embodiment, at least 20, at least 30, at least 40, at least 50, at least 60, at least 70, at least 80, at least 90, at least 100 doses of enzyme replacement therapy for hypophosphatasia. In some embodiments, the subject has previously received a total of 6 to 9 mg / kg / week for at least one month, at least two months, at least six months, at least 12 months, at least 24 months, at least 48 months. In some embodiments, the subject has previously received a total of 6 to 9 mg / kg / week for more than five years. In one embodiment, the subject’s plasma alkaline phosphatase (ALP) level after single dose of gene therapy of the invention and discontinuation of ERT is within the therapeutic range of the ALP level during continued ERT without gene therapy. Certain embodiments of the disclosure are directed to a method of treating hypophosphatasia (HPP) in a subject in need thereof, the method comprising administering a plasmid (e.g. a viral plasmid) of the invention, an isolated polynucleotide of the invention, a recombinant virus of the invention, a host cell of the invention, or the pharmaceutical composition of the invention to the subject in need thereof. In one embodiment, the administration is intravenous injection. In one embodiment, the administration is a single dose. In one embodiment, the single dose is administered by a single or multiple injections. In one embodiment, the administration is at multiple sites by intravenous injection. In some embodiments, the HPP is perinatal, infantile, juvenile, or adult HPP. In some embodiments, HPP is the severe infantile form of HPP. In one embodiment, the subject is an infant or a juvenile. In one embodiment, the subject is an adult. The normal range for serum alkaline phosphatase (ALP) levels in healthy adults is between about 35 to 145 IU / L. In one embodiment, the subject’s ALP activity is persistently low considering the age and sex adjusted normal range, compared to a healthy subject. In some embodiments, the subject does not develop ectopic calcification or abnormal calcium metabolism after administration. In some embodiments, the subject does not develop ectopic calcification or abnormal calcium metabolism within 3 months, within 4 months, within 5 months or within 6 months after administration. In some embodiments, the recombinant sTNAP expression from the viral plasmid is not detected in vasculature cells after administration. In some embodiments, the recombinant sTNAP expression from the viral plasmid is not detected in vasculature cells within 3 months, within 4 months, within 5 months or within 6 months after administration. Detection methods include, for example, quantitative PCR or tissue staining with nucleic acid hybridization probes. In one embodiment, the viral plasmid gDNA content in heart, aorta and muscle tissue is less than 10% relative to the viral plasmid gNDA content in liver tissue. In one embodiment, the viral plasmid gDNA content in heart, aorta and muscle tissue is less than 5% relative to the viral plasmid gNDA content in liver tissue. In one embodiment, the viral plasmid gDNA content in heart, aorta and muscle tissue is less than 2% relative to the viral plasmid gNDA content in liver tissue. In one embodiment, the viral plasmid gDNA content is measured as the relative median fractional gDNA content determined by quantitative PCR (qPCR). Moreover, the plasma activity of sTNAP provided by the viral plasmid of the invention is sufficient to treat symptoms of HPP other than bone and / or teeth mineralization defects. Particularly, the viral plasmid of the invention has sufficient activity to treat brain symptoms of HPP. Hence, in one embodiment, the viral plasmid for use according to the invention reduces seizures in a subject. The subject may suffer from diagnosed or undiagnosed HPP. Such seizures may be responsive or nonresponsive to vitamin B6 and / or other traditional anti-seizure drug treatment(s). Further Embodiments The invention is also described by the following items: 1. A viral plasmid comprising a recombinant gene expression cassette, the recombinant gene expression cassette comprising: a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof; b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a); and d) a polynucleotide encoding a hydroxyapatite binding domain; wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae. 2. The viral plasmid of item 1, wherein the regulatory element of b) is a tissue specific promoter. 3. The viral plasmid of any one of the preceding items, wherein the tissue specific promoter is a liver-specific promoter. 4. The viral plasmid of any one of the preceding items, wherein the hydroxyapatite binding domain is poly-aspartic acid and / or poly-glutamic acid, optionally comprising between six and fifteen continuous residues, preferably wherein the hydroxyapatite binding domain is decapeptide aspartic acid (D10). 5. The viral plasmid of any one of the preceding items, wherein the hydroxyapatite binding domain is C-terminal relative to sTNAP. 6. The viral plasmid of any one of the preceding items, wherein the expression product of the gene expression cassette is a fusion protein comprising in order from N-terminal to C-terminal the sTNAP and the hydroxyapatite binding domain. 7. The viral plasmid of any one of the preceding items, wherein the polynucleotide encoding the regulatory element is upstream of the polynucleotide encoding sTNAP. 8. The viral plasmid of any one of the preceding items, wherein the polynucleotide a) encodes an amino acid that is at least 70% identical to the amino acid set forth in SEQ ID NO: 2. 9. The viral plasmid of any one of the preceding items, wherein the polynucleotide a) comprises a nucleic acid that is at least 90% identical to the nucleic acid set forth in SEQ ID NO: 1. 10. The viral plasmid of any one of the preceding items, wherein the polynucleotide b) comprises a nucleic acid that is at least 70% identical to the nucleic acid set forth in SEQ ID NO: 3. 11. The viral plasmid of any one of the preceding items, wherein the polynucleotide d) comprises a nucleic acid that is at least 70% identical to the nucleic acid set forth in SEQ ID NO: 4. 12. The viral plasmid of any one of the preceding items, wherein the at least one ITR is from an adeno-associated virus (AAV). 13. The viral plasmid of any one of the preceding items, wherein the at least one ITR is from AAV2. 14. The viral plasmid of any one of the preceding items, wherein the at least one ITR comprises a 5’ ITR and a 3’ ITR flanking the recombinant gene expression cassette. 15. The viral plasmid of item 14, wherein the nucleic acid sequence of the 5’ ITR is at least 90% identical to the nucleic acid sequence set forth in SEQ ID NO: 7 and the nucleic acid sequence of the 3’ ITR is at least 90% identical to the nucleic acid sequence set forth in SEQ ID NO: 8. 16. The viral plasmid of any one of the preceding items, wherein the recombinant gene expression cassette further comprises e) one or more miRNA binding sites 17. The viral plasmid of any one of the preceding items, wherein the one or more miRNA binding sites are between the hydroxyapatite binding domain and the C-terminus in the transcript encoded by the recombinant gene expression cassette. 18. The viral plasmid of any one of the preceding items, wherein the one or more miRNA binding sites are recognised by miR1261-5p. 19. The viral plasmid of any one of the preceding items, wherein the one or more miRNA binding sites comprises a nucleic acid sequence at least 70% identical to the nucleic acid sequence as set forth in SEQ ID NO: 9. 20. The viral plasmid of any one of the preceding items, wherein the recombinant gene expression cassette further comprises f) a polynucleotide comprising one or more 5’ intron sequences; and / or g) a polynucleotide comprising one or more Woodchuck Hepatitis Virus posttranscriptional regulatory element (WPRE) sequences. 21. The viral plasmid of any one of claims 1 to 20, wherein the recombinant expression cassette further comprises c) a polynucleotide encoding a stabilizing domain, optionally wherein the stabilizing domain is an Fc domain. 22. An isolated polynucleotide comprising the viral plasmid of any one of items 1 to 21. 23. A recombinant virus comprising the recombinant gene expression cassette as defined in any one of items 1 to 21 and a capsid. 24. The recombinant virus of item 23, wherein the capsid is from a virus of the family Parvoviridae. 25. The recombinant virus of any one of items 23 or 24, wherein the capsid is from a virus of the family Parvoviridae exhibiting liver tropism. 26. The recombinant virus of any one of items 23 to 25, wherein the capsid is from AAV8. 27. The recombinant virus of any one of items 23 to 26, wherein the capsid is from AAV8 and is the recombinant gene expression cassette is flanked by two ITRs from AAV2. 28. The recombinant virus of any one of items 23 to 27, wherein the recombinant virus does not exhibit muscle tropism. 29. A host cell comprising the viral plasmid of any one of items 1 to 21, the isolated polynucleotide of item 22, or the recombinant virus of any one of items 23 to 28. 30. A pharmaceutical composition comprising the viral plasmid of any one of items 1 to 21, the isolated polynucleotide of item 22, the recombinant virus of any one of items 23 to 28, or the host cell of item 29, and optionally one or more excipients. 31. The viral plasmid of any one of items 1 to 21, the isolated polynucleotide of item 22, the recombinant virus of any one of items 23 to 28, the host cell of item 29, or the pharmaceutical composition of item 30 for use as a medicament. 32. The viral plasmid of any one of items 1 to 21, the isolated polynucleotide of item 22, the recombinant virus of any one of items 23 to 28, the host cell of item 29, or the pharmaceutical composition of item 30 for use in gene therapy. 33. The viral plasmid of any one of items 1 to 21, the isolated polynucleotide of item 22, the recombinant virus of any one of items 23 to 28, the host cell of item 29, or the pharmaceutical composition of item 30 for use in the treatment of pyrophosphate deposition diseases in a subject in need thereof. 34. The viral plasmid, the isolated polynucleotide, the recombinant virus, the host cell, or the pharmaceutical composition for use according to item 33, wherein the treatment increases mineralization in bone tissue in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. 35. The viral plasmid, the isolated polynucleotide, the recombinant virus, the host cell, or the pharmaceutical composition for use according to item 33, wherein the treatment increases the ratio of extracellular Pi to PPi in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases. 36. The viral plasmid, the isolated polynucleotide, the recombinant virus, the host cell, or the pharmaceutical composition for use according to any one of items 33 to 36, wherein the pyrophosphate deposition disease is hypophosphatasia (HPP). 37. The recombinant virus for use according to any one of items 31 to 36, wherein the recombinant virus is administered to a subject in need thereof at a dose of up to 3 x 1013 vg / kg. 38. The recombinant virus for use according to any one of items 31 to 37, wherein the recombinant virus is administered to a subject who has previously received enzyme replacement therapy for hypophosphatasia. 39. The recombinant virus for use according to item 38, wherein the subject has previously received at least ten daily doses of enzyme replacement therapy for hypophosphatasia. Examples Example 1: Addition of Fc domain to the gene therapy cassette results in higher serum sTNAP activity The in vivo testing included up to five male C57 / BI6 mice per group. The animals received a single intravenous bolus injection of 1 x 1013 vg / kg of the test items in a volume of 5 mL / kg. Retroorbital blood samples were collected before dosing and at 2 and 4 weeks after dosing. At the end of the in-life phase, blood samples collected by cardiac puncture and organs were collected from all mice. Alkaline phosphatase activity in serum samples is determined using Alkaline Phosphatase Activity Fluorometric Assay Kit (Abeam, Cat#AB83371). In brief, ALP (sTNAP) cleaves the phosphate group of the non-fluorescent 4-methylumbelliferyl phosphate disodium salt (MUP) substrate resulting in an intense fluorescent signal (Ex / Em = 360 nm 1440 nm). Test samples were appropriately diluted in assay buffer, mixed with MUP substrate in assay buffer. Activity in test samples was determined by MUP standards with recombinant ALP enzyme. Reactions were incubated at 25°C for 30 minutes and Stop Solution added before fluorescence intensity was determined by a microtiter plate reader. Vector copy number was determined in liver tissue collected from exsanguinated mice. Tissue processing and isolation of DNA (genomic DNA and vector DNA) was performed. DNA was applied to quantitative PCR assay detecting the transgene DNA with transgene specific primers and probe (vs. an endogenous gene). Vector-specific primers were LAUDA-forward GGTGGAAGGAGGCAGAATTG (SEQ ID NO: 15), LAUDA-probe CACGGGCACCATGAA (SEQ ID NO: 16) and LAUDA-reverse GGGCCTGCTTGGCTTTTC.(SEQ ID NO: 17). Vector TNAP copy number per microgram genomic DNA was calculated. Serum sTNAP activity was significantly higher in mice treated with AAV8-STNAP-FC-D10 (L01, LaudaOI) than in mice treated with AAV8-STNAP-D10 (L02, Lauda02) or AAV8-STNAP (L03, Lauda03) (Figure 1A). Similar vector copy numbers in liver indicate similar transduction efficiencies in the three treated groups (Figure 1B). Hence, the presence of an Fc domain in the transgene constructs significantly improved sTNAP enzymatic activity in serum. Transgene constructs are depicted in Figure 10. Example 2: Addition of D10 domain to the gene therapy cassette results in interaction with bone mineral (hydroxyapatite) 2 x 105 Huh-7 cells were seeded per well of a 24-well plate (Costar, Cat.No. 3524) in 500pl of culture media (DMEM 4,5g / L D-Glucose + 2mM L-Glutamine; Gibco, Cat.No. 11965-092; + 10% FBS) 24h prior to transfection. Huh-7 cells were transfected with 500ng DNA / well of the different TNAP constructs using jetOPTIMUS reagent (Polyplus, Cat. No. 101000025). Media was changed to Freestyle F17 expression media (Invitrogen; Cat. No. A13835) supplemented with 4mM glutamine (Invitrogen; Cat. No. 25030) 5h after transfection. The supernatants were collected 72h after transfection and alkaline phosphatase (ALP) activity was determined using Alkaline Phosphatase Fluorometric Assay Kit (Abeam, Cat#AB83371) according to manufacturer’s recommendations. Supernatants containing different sTNAP constructs and Strensiq (Alexion, Cat. No. EV30829) were diluted in Freestyle F17 expression media to final ALP concentrations of 40mU / ml and 10mU / ml. Dilutions of 2.5mM hydroxyapatite (HA; Sigma-Aldrich Handels GmbH, Cat. No. 677418-5G) and calcium carbonate (CC; Sigma Aldrich Handels GmbH, Cat. No. 693781) in 2% BSA (Sigma-Aldrich Handels GmbH, Cat. No. A3294-50G) were prepared. To study the interaction of sTNAP with HA and CC, 300pl / reaction of the respective salt solution was initially transferred to a 1.5ml tube, centrifuged at 15000rpm for 1 minute and the supernantant was discarded. Next, 300pl of the different sTNAP dilutions were combined with the salt pellets and incubated for 30 minutes at 37°C in a heating block while shaking (300rpm). After the incubation, the samples were centrifuged at 15000rpm for 1 minute. Supernatants were collected for ALP activity determination after exposure to hydroxyapatite and calcium carbonate. Pellets were discarded. ALP depletion after incubation with HA and CC was determined. The results show that Alkaline Phosphatase activity was depleted by hydroxyapatite but not calcium carbonate, meaning that the enzyme was removed from the test system by binding to hydroxyapatite but not calcium carbonate (Figure 2). Example 3: AAV-sTNAP-Fc-D10 confers efficacious serum sTNAP activity in TNAP deficient mice into adulthood The in vivo testing included up to eight TNAP-deficient ALP' / _ knock-out mice (B6; 129S7-Alpltm1Sor / J, JAX stock No 002317) or ALP+ / + wild-type littermate new-born mice per group. The animals received either daily ERT (subcutaneous application of Asfotase Alfa 8.2 mg / kg / d (Strensiq®)) or a single intravenous bolus injection of an AAV8-STNAP-FC-D10 vector (i.e. LaudaOI) on or about day 2 post natum. The mice received either 1 x 1014 vg / kg (about 2 x 1011 vg / body) or 1 x 1013 vg / kg (about 2 x 1010 vg / body). Serum activity of sTNAP was determined as described above in Example 1. Peripheral blood samples were collected at 2 week time-intervals from the age of 4 / 5 weeks up to 16 weeks. At the end of the in-life phase, animals were exsanguinated by saline-perfusion and organs collected from all surviving mice. Survival of mice was 100% in the 1 x 1014 vg / kg dose group, and 50% in the 1 x 1013 vg / kg dose group. Serum TNAP activity was significantly higher in the 1 x 1014 vg / kg dose group on day 28 and was durable into adulthood and relatively unchanged to study end (week 16). Serum activity in the 1 x 1013 vg / kg dose group was equivalent to the group treated daily with ERT, and serum activity was durable into adulthood and relatively unchanged to study end (week 16). ERT treatment in the ERT dose group was discontinued on day 28. Vehicle treated wild-type mice show relatively low endogenous serum ALP activity as expected. These results show that a single injection with the AAV8-STNAP-FC-D10 vector at low concentration can provide equivalent serum activity of ALP compared to daily ERT dosing, while a single injection with the AAV8-STNAP-FC-D10 vector at higher concentration significantly outperforms ERT therapy (Figure 3A). Surprisingly, the serum ALP activity stayed consistent throughout the 16 week study period (Figure 3B). Example 4: Liver directed transgene AAV-sTNAP-Fc-D10 confers survival in newborn TNAP deficient mice and can replace enzyme replacement therapy. The in vivo testing included up to ten TNAP deficient ALP' / _ knock-out (B6; 129S7-Alpltm1Sor / J, JAX stock No 002317) or ALP+ / + wild-type littermate new-born mice per group. The neonatal mice were administered a single intravenous bolus injection of AAV8-HLP:sTNAP*-FC-D10-miRBS vector (Archl 1, sTNAP* represents codon-optimized sTNAP, miRBS refers to micro RNA binding sites) on or about day 2 (1 x 1014 vg / kg or about 2 x 1011 vg / body). Arch04 was included in the study representing a vector lead without codon-optimization and without miRNA binding sites, i.e. AAV8-HLP:sTNAP-FC-D10. Transgene constructs are depicted in Figure 4B. An overview of the study is shown in Figure 10. The study was conducted using the HPP mouse model, a Alpl-'- homozygous knock out mouse line. This mouse usually has a limited life-span of about 2 weeks. Treatments were started on postnatal day 2 in all treatment groups and continued up to day 59. The study was separated into two blocks of 4 weeks each (see Figure 10). The following treatment groups were included in the study: 1) WT(Alpr'+y 2) KO (knock-out, Alpl-'-) vehicle treated, no active agent (buffer); 3) KO (Alpl-'-) treated with enzyme replacement therapy (ERT) s.c. 8.2 mg / kg / d daily between day 2 and day 59 “ERT d1-d59”; 4) KO (Alpl'1') treated with ERT s.c. 8.2 mg / kg / d daily for only half of the study, between day 2 and day 28 “ERT d1-d28”; 5) KO (Alpl'1') treated with ERT s.c. 8.2 mg / kg / d daily for only half of the study, between day 2 and day 28, followed by a single intravenous injection of 1 x 1014 vg / kg AAV carrying the gene therapy vector Archl 1 on day 29 “ERT d1-d28 GT d29”; 6) KO (Alpl''-) treated with a single intravenous injection of 1 x 1014 vg / kg AAV carrying the gene therapy vector Archl 1 on day 2 at the start of the study “GT d2”. Note that besides the survival curve, no data was collected for the untreated KO group 2), since all animals died within 2 weeks of the study. A separate group of ALP' / _ mice received systemic administration of ERT in the form of daily subcutaneous application of Asfotase Alfa (i.e. Strensiq®) 8.2 mg / kg / d as a technical control (subcutaneous route). Peripheral blood samples were collected at 2 or 4 weeks’ time-intervals from the age of 28 days up to day 59. At the end of the in-life phase, animals were exsanguinated by saline-perfusion and organs collected from all surviving mice. At day 59, animals were sacrificed and data was collected. Data collection included biomarkers, plasma TNAP activity, vector biodistribution, gNDA and cDNA, Femur / Tibia ex-vivo analyses, Longitudinal bone growth (bone length), Bone microCT, Bone Strength, Ash weight, Histochemistry of Liver and Aorta. Vector copy number and vector RNA expression were determined in the respective tissues of surviving mice at study end (day 59) by quantitative PCR using transgene specific primers and probes. The aim of this study was to assess the in vivo biopotency / efficacy (survival and bone phenotype), the tissue specificity (liver vs. heart, aorta, skeletal muscle) and durability of expression, and activity of in vivo liver-targeted GT(gene therapy) (intravenous route) in the neonatal mouse. As a further goal this study tested the feasibility of discontinuation of treatment with ERT (ERT d1-d28), and the continuation of treatment with gene therapy on day 29 (single i.v. injection Archil, 1e14 vg / kg; ERT d1-d28 GT d29). TNAP activity in serum was assessed as described above. Femoral length was determined by caliper as a phenotypic indicator of longitudinal bone growth at study end. As shown in Figure 4, overall survival in ALP^mice was comparable in mice that received 28 days of ERT followed by one injection of gene therapy vector (ERT d1-d28 -> GT d29) and mice that received 59 days of ERT (ERT d1-d59), demonstrating that daily ERT can be discontinued and followed by treatment with GT. Treatment by injection of the gene therapy vector at day 2 also significantly improved overall survival (GT d2). Overall, the study shows a proof of principle for rescue of HPP lethality in infantile mouse (i.e. treatment of naive newborn subjects). Durability of TNAP expression after gene therapy was observed into adulthood (week 9-10). Treatment of ERT-experienced juvenile subjects provides a proof of principle for therapy switch from ERT to gene therapy (group 5). Example 5: Liver directed transgene AAV-sTNAP-Fc-D10 confers pharmacodynamic benefit in serum activity and bone growth in TNAP deficient mice and can replace enzyme replacement therapy. In vivo experiments were performed as described in Example 4. Serum activity of sTNAP was determined as described above in Example 1 (Figure 5A). Discontinuation of treatment with ERT on d28 resulted in shorter femura in the respective group at study end (day 59) than those in the group where treatment was continued with gene therapy (ERT d1-d28 GT d29) (Figure 5B). There was no significant difference in groups where treatment with ERT was not discontinued (ERT d1-d59) vs. groups treated with Arch-11. Example 6: Transduction of transgene AAV8-HLP-sTNAP-FC-D10-MIRBS (Archil) is specific in targeted liver tissue over non-target tissue when treated as newborn or juvenile mouse. In vivo experiments were performed as described in Example 4. The relative transgene gDNA content and RNA expression was highest in liver tissue. In sTNAP deficient mice dosed intravenously at 4 week of age, the median fractional gDNA content (vs. liver tissue 100%) in the heart, aorta and quadriceps was 0.5%, 1.6% and 0.5% respectively. The median fractional RNA (cDNA) expression (vs. liver tissue 100%) in the heart, aorta and quadriceps was 0.4%, 0.1% and 0.0% respectively (Figure 6). Example 7: Addition of miRNA binding sites to AAV-sTNAP-Fc-D10 results in reduced off-target expression of the transgene Micro RNA (miRNA, miR) expression profiling was done by quantitative RT-PCR in a human cell panel as indicated in Table 1. Cells lines were screened for miRNAs 5 expression patterns displaying a desirable profile: a high ratio of expression in off-target tissue / on-target-tissue, indicated by Low Ct value in off-target cells (Ct-value <30) and relatively higher Ct value in liver cells (Ct-value >30) was deemed a desirable profile. The results of the screen are shown in Figure 7. Table 1: Overview of cell lines used for miRNA expression profiling. HUVEC Human Umbilical Vein Endothelial Cells HCAEC Human Coronary Artery Endothelial Cells DAoEC Human Aortic Endothelial Cells HCMEC Human Cardiac Microvascular Endothelial Cells HCASMC Human Coronary Artery Smooth Muscle Cells HAoSMC Human Aortic Smooth Muscle Cells SkMC Human Skeletal Muscle Cells HCM Human Cardiac Myocytes hFOB 1.19 Human Fetal Osteoblasts U2OS Human Osteosarcoma HepG2 Human Hepatocellular Carcinoma Cells Huh-7 Human Hepatocellular Carcinoma Cells THP-1 Human Monocytic Cells miRNA126-3p, miRNA-126-5p, miRNA-143-3p, miRNA145-5p were selected from the screen. miRNA126-3p and miRNA-126-5p are expressed at high levels in Human vascular and microvascular endothelial cells (HUVEC, HCAEC, HAoEC, HCMEC) and in vascular smooth muscle cells (HCASMC, HAoSMC). miRNA-143-3p, miRNA145-5p are expressed at high levels in Human vascular smooth muscle cells (HCASMC, HAoSMC). miRNA126-3p, miRNA-126-5p, miRNA-143-3p, miRNA145-5p are expressed at relatively low levels in Human cell lines derived from liver (HepG2, Huh-7). As an additional feature miRNA126-3p, miRNA-126-5p, miRNA-143-3p, miRNA145-5p are expressed at relatively lower levels in in Human cell lines derived from bone (hF0B1.19, U2OS). Associated miRNA bindings sites were further functionally tested. In particular, multiple miRNA126-5p binding sites were encoded 3’ of the protein coding sequence of transgene within DNA of expression cassettes, e.g. 4x 126-5p (Senna08) and 2x 126-5p (Senna14), vectorized and used in transduction experiments in liver-derived cell lines or HUVEC. Repression of activity in transduced HUVEC cells / absence of repression in human liver-derived cell line in-vitro after transduction with AAV6 based vectors. All vectorized expression constructs use the same constitutive CMV promoter for comparison of miRNA binding site function. The constructs were vectorized (AAV6) and used to transduce HepG2 cells (liver cells, on-target) or HUVEC cells (vascular cells, non-target) [0,25pM Doxorubicin, 0,25pM MG132, MOI: 2 x 104] in-vitro. Enzyme activities were determined in cell culture supernatants of transduced cells. Suppression in HUVEC cells by miRNA binding sites was calculated about 77 to 89-fold (L01: LaudaOI-cassette; S14 / 08: Senna14 and Senna08-cassettes containing 2x and 4x miRNA binding sites respectively). The Senna 14 2x miRNA binding site sequence was also used in Archl 1. As shown in Figure 8, secreted ALP activity in transduced cells was high in liver cells and low in vascular cells, which indicates that the transgene was repressed by miR126 in the off-target vasculature cells. Example 8: Dose-exposure relationship in mice suggests highly efficacious sTNAP activity levels in plasma and allows extrapolation of effective human starting dose Archil was dosed intravenously to wild type mice at 8 x 1013, 1 x 1013, 3 x 1012 or 1 x 1012 vg / kg and enzyme activity was determined in plasma 4 weeks after dosing. Assuming that one mouse pup had a body weight of approximately 2g at administration, the doses were about 1.6 x 1011, 2 x 1010, 6 x 109 or 2 x 109 vg per body. There was a clear dose response relationship. As expected, activity in plasma of vehicle treated wildtype mice is relatively low (8.5-13.9 mU / mL). Strensiq was dosed to mice subcutaneously at high-doses (8.2 mg / kg / day), sALP-FcD10, this dose to conferred normal growth and mice appeared well without skeletal disease or epilepsy. This treatment has previously been reported to prevent hypomineralization of alveolar bone, dentin, and cementum as assessed by micro-computed tomography and histology in a mouse model of HPP (ref Yadav et al. (2011) Bone 49(2): 250-256.). Activity in plasma was determined 6 hours after a single-dose Strensiq administered to wild-type mice („peak exposure"), or after daily dosing of Strensiq for 4 or 6 weeks to HPP mice (..trough exposure"). The plasma activity in Arch-11 treated mice was substantially higher than in mice treated with Strensiq (Figure 9). Activity in plasma of Arch-11 low dose (1.0 x 1012 vg / kg) group was higher or similar than in mice dosed with Strensiq, suggesting an efficacious dose level for gene therapy in the mouse (Figure 9). Several methods can be considered for prediction of a human dose (Zou (2022) BJCP 89(4):1393-1401), including prediction of AAV8-based and HLP promoter-based gene therapy and expression of secreted transgene (hFVIll, human Factor VIII) product by the human liver (i.e. rAAV8-HLPhFVIII-V3). In general, a factor 20x-30x can be applied in the scaling from mouse to human doses suggesting a reasonable, effective and feasible Arch-11 starting dose for a clinical trial. Hence, a extrapolated starting dose for a clinical trial in human subjects is estimated 2 x 1013 to 3 x 1013 vg / kg. Example 9: Amelioration of bone phenotype in Alpl z' knockout mice Bone biomechanical testing shown that gene therapy improves bone mineralization and strength in the femur. Figure 11 shows the weight of the bone ash of the femur (A) and cantilever bending test of the femur, which determines the maximum load the bone can bend before it fractures. GT in newborn mice was similarly efficacious as daily treatments with ERT. Discontinuation of ERT on day 28 was well tolerated but resulted in reduced mineralization (ash weight) and reduced bone strength. Treatment of ERT-experienced juvenile subjects rescued mineralization and bone strength comparable to continued daily ERT on day 59. Figure 12 shows that gene therapy improves bone mineralization and strengths in the tibia. GT in newborn mice was similarly efficacious as daily treatments with ERT. Discontinuation of ERT on day 28 was well tolerated but resulted in reduced mineralization (ash weight) and reduced bone strength. Treatment of ERT-experienced juvenile subjects rescued mineralization and bone strength comparable to continued daily ERT on day 59. Figure 13 shows results from micro-computed tomography (micro-CT). Gene therapy improves bone mineral density and bone volume in distal femur metaphysis, and positively affects trabecular bone number: GT in newborn mice was similarly efficacious as daily treatments with ERT. Discontinuation of ERT on day 28 was well tolerated but resulted in reduced BMD, bone volume and Tb.N. Treatment of ERT-experienced juvenile subjects rescued BMD and trabecular structure comparable to continued daily ERT on day 59, and comparable to data in tibiae of wt-mice. Figure 14 shows results from micro-CT. Gene therapy improves bone mineral density and bone volume in femur diaphysis, and positively affects cortical bone: GT in newborn mice was similarly efficacious as daily treatments with ERT. Discontinuation of ERT on day 28 was well tolerated but resulted in reduced diaphyseal BMD, bone volume and cortical bone parameters. Treatment of ERT-experienced juvenile subjects rescued cortical bone structure comparable to continued daily ERT (day 59), and comparable to data collected in tibiae of wild-type mice. Figure 15 shows representative images from micro-CT. Example 10: Histochemistry of liver and aorta of mice Von Kossa staining was performed using a Von Kossa Staining Kit from Abeam #ab150687 according to the kit instructions. Figure 16A shows positive signal of the von Kossa staining in the mouse femur, highlighting calcium deposits in the bone (dark and black staining). Figure 16B shows that there were no calcium deposits detected in the mouse liver after gene therapy. Figure 16C shows that there were no calcium deposits detected in the mouse aorta after gene therapy. Immunohistochemistry staining was performed using a primary antibody anti-human Alkaline Phasphatase (rabbit) Abeam #ab305305, dilution 1:1000 at pH9, and secondary antibody CF647 donkey anti-rabbit, Biotium #20047 dilution 1:1000. Figure 17 shows that human alkaline phosphatase protein was detected in the liver of animals that had received gene therapy, but not in the aorta of the same animals. No human alkaline phosphatase protein was detected in animals injected with vehicle. Sequences SEQ ID NO: 1 sTNAP codon optimized nucleic acid sequence atggtcagccccttcctggtgctggccatagggacctgcctgaccaactccctggtgccagagaaggagaaggacccca agtactggagggatcaagcccaagagaccctgaagtatgccctggagctgcagaagctcaacaccaatgtggccaag aatgtcatcatgttcctgggggatggcatgggggtgagcacagtcacagctgccagaatcctcaaggggcagctccacca caaccctggagaggagacaaggctggagatggacaagttcccctttgtggccctcagcaagacctacaataccaatgcc caagtgcctgactctgctggcacagccactgcctacctgtgtggggtgaaggccaatgagggcactgtgggggtgtcagct gccacagagaggagccgctgcaacaccacccaagggaatgaagtgaccagcatcctgagatgggccaaggatgctg ggaagtcagtgggcattgtcaccaccaccagagtcaaccatgccaccccctcagcagcctatgcccactctgctgatagg gactggtactctgacaatgagatgcccccagaggccctgtcccaaggctgcaaggacattgcctaccagctgatgcaca acatccgggacattgatgtgatcatggggggtgggaggaagtatatgtaccccaagaacaagacagatgtggagtatga gtctgatgagaaggctaggggcacccggctggatggcctggacctggtggacacctggaagtccttcaagccaaggtac aagcactcccacttcatctggaacagaactgagctgctgaccctggacccccacaatgttgactacctcctgggcctgtttg agcctggggacatgcagtatgaactgaaccgcaacaatgtgactgaccccagcctgtctgagatggttgtggtggccatcc agatcctgcgcaagaaccccaaggggttctttctgctggtggagggggggaggattgaccatggccaccatgaggggaa ggccaagcaagccctccatgaggctgtggaaatggatagggccattgggcaagctggctccctgacctccagtgaggac accctgactgtggtcactgctgaccacagccatgtcttcacctttggaggctacacacccagaggcaactccatctttgggct ggcccccatgctctcagacacagacaagaagcccttcacagccatcctgtatggcaatggccctgggtacaaggtggtg gggggggagagggagaatgtgtccatggtggactatgcccataacaactaccaagcccagtctgcagtgcccctgagg catgagacccatggaggggaggatgtggctgtcttcagcaagggccccatggcccacctgctgcatggggtccatgagc agaactatgtcccccatgtgatggcctatgctgcctgcattggggccaacctgggccactgtgcccctgcctcctct SEQ ID NO: 2 sTNAP amino acid sequence MVSPFLVLAIGTCLTNSLVPEKEKDPKYWRDQAQETLKYALELQKLNTNVAKNVIMFLG DGMGVSTVTAARILKGQLHHNPGEETRLEMDKFPFVALSKTYNTNAQVPDSAGTATAY LCGVKANEGTVGVSAATERSRCNTTQGNEVTSILRWAKDAGKSVGIVTTTRVNHATPS 78 AAYAHSADRDWYSDNEMPPEALSQGCKDIAYQLMHNIRDIDVIMGGGRKYMYPKNKT DVEYESDEKARGTRLDGLDLVDTWKSFKPRYKHSHFIWNRTELLTLDPHNVDYLLGLF EPGDMQYELNRNNVTDPSLSEMVVVAIQILRKNPKGFFLLVEGGRIDHGHHEGKAKQA LHEAVEMDRAIGQAGSLTSSEDTLTVVTADHSHVFTFGGYTPRGNSIFGLAPMLSDTDK KPFTAILYGNGPGYKVVGGERENVSMVDYAHNNYQAQSAVPLRHETHGGEDVAVFSK GPMAHLLHGVHEQNYVPHVMAYAACIGANLGHCAPASS SEQ ID NO: 3: Hybrid liver promoter nucleic acid sequence gcacgcgtgtgtttgctgcttgcaatgtttgcccattttagggtggacacaggacgctgtggtttctgagccagggggcgactc agatcccagccagtggacttagcccctgtttgctcctccgataactggggtgaccttggttaatattcaccagcagcctcccc cgttgcccctctggatccactgcttaaatacggacgaggacagggccctgtctcctcagcttcaggcaccaccactgac SEQ ID NO: 4: D10 nucleic acid sequence gatgacgacgatgatgacgatgatgacgac SEQ ID NO: 5: Fc domain nucleic acid sequence gacaagacccacacctgccccccctgccctgccccagagctgctgggggggccctctgtgttcctcttcccccccaagcc caaagacaccctcatgatctccagaaccccagaggtgacatgtgtggtggtggatgtctcccatgaggaccctgaggtca aattcaactggtatgtggatggggtggaggtgcacaatgccaagaccaagcctagggaggagcagtacaacagcacct acagagtggtgtctgtcctcactgtcctgcaccaagactggctgaatgggaaggagtacaagtgcaaggtcagcaacaa ggccctgccagcccccattgagaagaccatcagcaaggccaagggccagccaagggagccccaagtctacaccctcc ccccctcaagggaggagatgaccaagaaccaagtgtccctcacctgcctggtcaagggcttctaccccagtgacattgct gtggagtgggagtccaatggccagcctgagaacaactacaagaccaccccccctgtgctggactcagatggcagcttctt cctgtactccaagctgacagtggacaagtctaggtggcagcaaggcaatgtcttctcctgcagtgtgatgcatgaggccctg cacaaccactacacccagaagagcctgtccctgagccctggcaag SEQ ID NO: 6: Fc domain amino acid sequence DKTHTCPPCPAPELLGGPSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWY VDGVEVHNAKTKPREEQYNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTI SKAKGQPREPQVYTLPPSREEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKT TPPVLDSDGSFFLYSKLTVDKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGK SEQ ID NO: 7: ITR 5’ nucleic acid sequence tgcaggcagctgcgcgctcgctcgctcactgaggccgcccgggcaaagcccgggcgtcgggcgacctttggtcgcccg gcctcagtgagcgagcgagcgcgcagagagggagtggccaactccatcactaggggttcct SEQ ID NO: 8: ITR 3’ nucleic acid sequence aggaacccctagtgatggagttggccactccctctctgcgcgctcgctcgctcactgaggccgggcgaccaaaggtcgcc cgacgcccgggctttgcccgggcggcctcagtgagcgagcgagcgcgcagctgcctgca SEQ ID NO: 9: 1x miRNA binding site nucleic acid sequence cgcgtaccaaaagtaataatg SEQ ID NO: 10: 2x miRNA binding site nucleic acid sequence cgcgtaccaaaagtaataatgtcacgcgtaccaaaagtaataatg SEQ ID NO: 11: Transgene / Fusion protein coding region nucleic acid sequence atggtcagccccttcctggtgctggccatagggacctgcctgaccaactccctggtgccagagaaggagaaggacccca agtactggagggatcaagcccaagagaccctgaagtatgccctggagctgcagaagctcaacaccaatgtggccaag aatgtcatcatgttcctgggggatggcatgggggtgagcacagtcacagctgccagaatcctcaaggggcagctccacca caaccctggagaggagacaaggctggagatggacaagttcccctttgtggccctcagcaagacctacaataccaatgcc caagtgcctgactctgctggcacagccactgcctacctgtgtggggtgaaggccaatgagggcactgtgggggtgtcagct gccacagagaggagccgctgcaacaccacccaagggaatgaagtgaccagcatcctgagatgggccaaggatgctg ggaagtcagtgggcattgtcaccaccaccagagtcaaccatgccaccccctcagcagcctatgcccactctgctgatagg gactggtactctgacaatgagatgcccccagaggccctgtcccaaggctgcaaggacattgcctaccagctgatgcaca acatccgggacattgatgtgatcatggggggtgggaggaagtatatgtaccccaagaacaagacagatgtggagtatga gtctgatgagaaggctaggggcacccggctggatggcctggacctggtggacacctggaagtccttcaagccaaggtac aagcactcccacttcatctggaacagaactgagctgctgaccctggacccccacaatgttgactacctcctgggcctgtttg agcctggggacatgcagtatgaactgaaccgcaacaatgtgactgaccccagcctgtctgagatggttgtggtggccatcc agatcctgcgcaagaaccccaaggggttctttctgctggtggagggggggaggattgaccatggccaccatgaggggaa ggccaagcaagccctccatgaggctgtggaaatggatagggccattgggcaagctggctccctgacctccagtgaggac accctgactgtggtcactgctgaccacagccatgtcttcacctttggaggctacacacccagaggcaactccatctttgggct ggcccccatgctctcagacacagacaagaagcccttcacagccatcctgtatggcaatggccctgggtacaaggtggtg gggggggagagggagaatgtgtccatggtggactatgcccataacaactaccaagcccagtctgcagtgcccctgagg catgagacccatggaggggaggatgtggctgtcttcagcaagggccccatggcccacctgctgcatggggtccatgagc agaactatgtcccccatgtgatggcctatgctgcctgcattggggccaacctgggccactgtgcccctgcctcctctcttaag gacaagacccacacctgccccccctgccctgccccagagctgctgggggggccctctgtgttcctcttcccccccaagcc caaagacaccctcatgatctccagaaccccagaggtgacatgtgtggtggtggatgtctcccatgaggaccctgaggtca aattcaactggtatgtggatggggtggaggtgcacaatgccaagaccaagcctagggaggagcagtacaacagcacct acagagtggtgtctgtcctcactgtcctgcaccaagactggctgaatgggaaggagtacaagtgcaaggtcagcaacaa ggccctgccagcccccattgagaagaccatcagcaaggccaagggccagccaagggagccccaagtctacaccctcc ccccctcaagggaggagatgaccaagaaccaagtgtccctcacctgcctggtcaagggcttctaccccagtgacattgct gtggagtgggagtccaatggccagcctgagaacaactacaagaccaccccccctgtgctggactcagatggcagcttctt cctgtactccaagctgacagtggacaagtctaggtggcagcaaggcaatgtcttctcctgcagtgtgatgcatgaggccctg cacaaccactacacccagaagagcctgtccctgagccctggcaaggatatcgatgacgacgatgatgacgatgatgac gactga SEQ ID NO: 12: Transgene / Fusion protein amino acid sequence MVSPFLVLAIGTCLTNSLVPEKEKDPKYWRDQAQETLKYALELQKLNTNVAKNVIMFLG DGMGVSTVTAARILKGQLHHNPGEETRLEMDKFPFVALSKTYNTNAQVPDSAGTATAY LCGVKANEGTVGVSAATERSRCNTTQGNEVTSILRWAKDAGKSVGIVTTTRVNHATPS AAYAHSADRDWYSDNEMPPEALSQGCKDIAYQLMHNIRDIDVIMGGGRKYMYPKNKT DVEYESDEKARGTRLDGLDLVDTWKSFKPRYKHSHFIWNRTELLTLDPHNVDYLLGLF EPGDMQYELNRNNVTDPSLSEMVVVAIQILRKNPKGFFLLVEGGRIDHGHHEGKAKQA LHEAVEMDRAIGQAGSLTSSEDTLTVVTADHSHVFTFGGYTPRGNSIFGLAPMLSDTDK KPFTAILYGNGPGYKVVGGERENVSMVDYAHNNYQAQSAVPLRHETHGGEDVAVFSK GPMAHLLHGVHEQNYVPHVMAYAACIGANLGHCAPASSLKDKTHTCPPCPAPELLGG PSVFLFPPKPKDTLMISRTPEVTCVVVDVSHEDPEVKFNWYVDGVEVHNAKTKPREEQ YNSTYRVVSVLTVLHQDWLNGKEYKCKVSNKALPAPIEKTISKAKGQPREPQVYTLPPS REEMTKNQVSLTCLVKGFYPSDIAVEWESNGQPENNYKTTPPVLDSDGSFFLYSKLTV DKSRWQQGNVFSCSVMHEALHNHYTQKSLSLSPGKDIDDDDDDDDDD SEQ ID NO: 13: Recombinant expression cassette nucleic acid sequence tgcaggcagctgcgcgctcgctcgctcactgaggccgcccgggcaaagcccgggcgtcgggcgacctttggtcgcccg gcctcagtgagcgagcgagcgcgcagagagggagtggccaactccatcactaggggttcctgatgatgcacgcgtgtgt ttgctgcttgcaatgtttgcccattttagggtggacacaggacgctgtggtttctgagccagggggcgactcagatcccagcc agtggacttagcccctgtttgctcctccgataactggggtgaccttggttaatattcaccagcagcctcccccgttgcccctctg gatccactgcttaaatacggacgaggacagggccctgtctcctcagcttcaggcaccaccactgacctgggacagtgaat ccctcgtgaattcgaattggatcctcgaggggcgcgccgccaccatggtcagccccttcctggtgctggccatagggacct gcctgaccaactccctggtgccagagaaggagaaggaccccaagtactggagggatcaagcccaagagaccctgaa gtatgccctggagctgcagaagctcaacaccaatgtggccaagaatgtcatcatgttcctgggggatggcatgggggtga gcacagtcacagctgccagaatcctcaaggggcagctccaccacaaccctggagaggagacaaggctggagatgga caagttcccctttgtggccctcagcaagacctacaataccaatgcccaagtgcctgactctgctggcacagccactgcctac ctgtgtggggtgaaggccaatgagggcactgtgggggtgtcagctgccacagagaggagccgctgcaacaccaccca agggaatgaagtgaccagcatcctgagatgggccaaggatgctgggaagtcagtgggcattgtcaccaccaccagagt caaccatgccaccccctcagcagcctatgcccactctgctgatagggactggtactctgacaatgagatgcccccagagg ccctgtcccaaggctgcaaggacattgcctaccagctgatgcacaacatccgggacattgatgtgatcatggggggtggg aggaagtatatgtaccccaagaacaagacagatgtggagtatgagtctgatgagaaggctaggggcacccggctggat ggcctggacctggtggacacctggaagtccttcaagccaaggtacaagcactcccacttcatctggaacagaactgagct gctgaccctggacccccacaatgttgactacctcctgggcctgtttgagcctggggacatgcagtatgaactgaaccgcaa caatgtgactgaccccagcctgtctgagatggttgtggtggccatccagatcctgcgcaagaaccccaaggggttctttctg ctggtggagggggggaggattgaccatggccaccatgaggggaaggccaagcaagccctccatgaggctgtggaaat ggatagggccattgggcaagctggctccctgacctccagtgaggacaccctgactgtggtcactgctgaccacagccatg tcttcacctttggaggctacacacccagaggcaactccatctttgggctggcccccatgctctcagacacagacaagaagc ccttcacagccatcctgtatggcaatggccctgggtacaaggtggtggggggggagagggagaatgtgtccatggtggac tatgcccataacaactaccaagcccagtctgcagtgcccctgaggcatgagacccatggaggggaggatgtggctgtctt cagcaagggccccatggcccacctgctgcatggggtccatgagcagaactatgtcccccatgtgatggcctatgctgcctg cattggggccaacctgggccactgtgcccctgcctcctctcttaaggacaagacccacacctgccccccctgccctgcccc agagctgctgggggggccctctgtgttcctcttcccccccaagcccaaagacaccctcatgatctccagaaccccagaggt gacatgtgtggtggtggatgtctcccatgaggaccctgaggtcaaattcaactggtatgtggatggggtggaggtgcacaat gccaagaccaagcctagggaggagcagtacaacagcacctacagagtggtgtctgtcctcactgtcctgcaccaagact ggctgaatgggaaggagtacaagtgcaaggtcagcaacaaggccctgccagcccccattgagaagaccatcagcaa ggccaagggccagccaagggagccccaagtctacaccctccccccctcaagggaggagatgaccaagaaccaagtg tccctcacctgcctggtcaagggcttctaccccagtgacattgctgtggagtgggagtccaatggccagcctgagaacaac tacaagaccaccccccctgtgctggactcagatggcagcttcttcctgtactccaagctgacagtggacaagtctaggtggc agcaaggcaatgtcttctcctgcagtgtgatgcatgaggccctgcacaaccactacacccagaagagcctgtccctgagc cctggcaaggatatcgatgacgacgatgatgacgatgatgacgactgataagcggccgcaatcaaagcttaccggtggt acccgcgtaccaaaagtaataatgtcacgcgtaccaaaagtaataatggttaaccaattgtctagagagcgctgcctcga gcctcgagagatctacgggtggcatccctgtgacccctccccagtgcctctcctggccctggaagttgccactccagtgccc accagccttgtcctaataaaattaagttgcatcattttgtctgactaggtgtccttctataatattatggggtggaggggggtggt atggagcaaggggcaagttgggaagacaacctgtagggcctgcggggtctattgggaaccaagctggagtgcagtggc acaatcttggctcactgcaatctccgcctcctgggttcaagcgattctcctgcctcagcctcccgagttgttgggattccaggc atgcatgaccaggctcagctaatttttgtttttttggtagagacggggtttcaccatattggccaggctggtctccaactcctaat ctcaggtgatctacccaccttggcctcccaaattgctgggattacaggcgtgaaccactgctcccttccctgtccttctgattttg taggtaaccacgtgcggcgatctcttgcaggcgatctctaggaacccctagtgatggagttggccactccctctctgcgcgct cgctcgctcactgaggccgggcgaccaaaggtcgcccgacgcccgggctttgcccgggcggcctcagtgagcgagcg agcgcgcagctgcctgca SEQ ID NO: 14 Viral plasmid complete nucleic acid sequence gcgatcgcttaaccctagaaagatagtctgcgtaaaattgacgcatgcaggcagctgcgcgctcgctcgctcactgaggc cgcccgggcaaagcccgggcgtcgggcgacctttggtcgcccggcctcagtgagcgagcgagcgcgcagagaggga gtggccaactccatcactaggggttcctgatgatgcacgcgtgtgtttgctgcttgcaatgtttgcccattttagggtggacaca ggacgctgtggtttctgagccagggggcgactcagatcccagccagtggacttagcccctgtttgctcctccgataactggg gtgaccttggttaatattcaccagcagcctcccccgttgcccctctggatccactgcttaaatacggacgaggacagggccc tgtctcctcagcttcaggcaccaccactgacctgggacagtgaatccctcgtgaattcgaattggatcctcgaggggcgcgc cgccaccatggtcagccccttcctggtgctggccatagggacctgcctgaccaactccctggtgccagagaaggagaag gaccccaagtactggagggatcaagcccaagagaccctgaagtatgccctggagctgcagaagctcaacaccaatgtg gccaagaatgtcatcatgttcctgggggatggcatgggggtgagcacagtcacagctgccagaatcctcaaggggcagc tccaccacaaccctggagaggagacaaggctggagatggacaagttcccctttgtggccctcagcaagacctacaatac caatgcccaagtgcctgactctgctggcacagccactgcctacctgtgtggggtgaaggccaatgagggcactgtggggg tgtcagctgccacagagaggagccgctgcaacaccacccaagggaatgaagtgaccagcatcctgagatgggccaag gatgctgggaagtcagtgggcattgtcaccaccaccagagtcaaccatgccaccccctcagcagcctatgcccactctgc tgatagggactggtactctgacaatgagatgcccccagaggccctgtcccaaggctgcaaggacattgcctaccagctga tgcacaacatccgggacattgatgtgatcatggggggtgggaggaagtatatgtaccccaagaacaagacagatgtgga gtatgagtctgatgagaaggctaggggcacccggctggatggcctggacctggtggacacctggaagtccttcaagcca aggtacaagcactcccacttcatctggaacagaactgagctgctgaccctggacccccacaatgttgactacctcctgggc ctgtttgagcctggggacatgcagtatgaactgaaccgcaacaatgtgactgaccccagcctgtctgagatggttgtggtgg ccatccagatcctgcgcaagaaccccaaggggttctttctgctggtggagggggggaggattgaccatggccaccatgag gggaaggccaagcaagccctccatgaggctgtggaaatggatagggccattgggcaagctggctccctgacctccagtg aggacaccctgactgtggtcactgctgaccacagccatgtcttcacctttggaggctacacacccagaggcaactccatctt tgggctggcccccatgctctcagacacagacaagaagcccttcacagccatcctgtatggcaatggccctgggtacaagg tggtggggggggagagggagaatgtgtccatggtggactatgcccataacaactaccaagcccagtctgcagtgcccct gaggcatgagacccatggaggggaggatgtggctgtcttcagcaagggccccatggcccacctgctgcatggggtccat gagcagaactatgtcccccatgtgatggcctatgctgcctgcattggggccaacctgggccactgtgcccctgcctcctctct taaggacaagacccacacctgccccccctgccctgccccagagctgctgggggggccctctgtgttcctcttcccccccaa gcccaaagacaccctcatgatctccagaaccccagaggtgacatgtgtggtggtggatgtctcccatgaggaccctgagg tcaaattcaactggtatgtggatggggtggaggtgcacaatgccaagaccaagcctagggaggagcagtacaacagca cctacagagtggtgtctgtcctcactgtcctgcaccaagactggctgaatgggaaggagtacaagtgcaaggtcagcaac aaggccctgccagcccccattgagaagaccatcagcaaggccaagggccagccaagggagccccaagtctacaccc tccccccctcaagggaggagatgaccaagaaccaagtgtccctcacctgcctggtcaagggcttctaccccagtgacatt gctgtggagtgggagtccaatggccagcctgagaacaactacaagaccaccccccctgtgctggactcagatggcagct tcttcctgtactccaagctgacagtggacaagtctaggtggcagcaaggcaatgtcttctcctgcagtgtgatgcatgaggcc ctgcacaaccactacacccagaagagcctgtccctgagccctggcaaggatatcgatgacgacgatgatgacgatgatg acgactgataagcggccgcaatcaaagcttaccggtggtacccgcgtaccaaaagtaataatgtcacgcgtaccaaaag taataatggttaaccaattgtctagagagcgctgcctcgagcctcgagagatctacgggtggcatccctgtgacccctcccc agtgcctctcctggccctggaagttgccactccagtgcccaccagccttgtcctaataaaattaagttgcatcattttgtctgact aggtgtccttctataatattatggggtggaggggggtggtatggagcaaggggcaagttgggaagacaacctgtagggcc tgcggggtctattgggaaccaagctggagtgcagtggcacaatcttggctcactgcaatctccgcctcctgggttcaagcga ttctcctgcctcagcctcccgagttgttgggattccaggcatgcatgaccaggctcagctaatttttgtttttttggtagagacggg gtttcaccatattggccaggctggtctccaactcctaatctcaggtgatctacccaccttggcctcccaaattgctgggattaca ggcgtgaaccactgctcccttccctgtccttctgattttgtaggtaaccacgtgcggcgatctcttgcaggcgatctctaggaac ccctagtgatggagttggccactccctctctgcgcgctcgctcgctcactgaggccgggcgaccaaaggtcgcccgacgc ccgggctttgcccgggcggcctcagtgagcgagcgagcgcgcagctgcctgcatatctctcgatccttgggctatcgaaac ttaattaaccagtcaagtcagctacttggcgagatcgacttgtctgggtttcgactacgctcagaattgcgtcagtcaagttcg atctggtccttgctattgcacccgttctccgattacgagtttcatttaaatcatgtgagcaaaaggccagcaaaaggccagga accgtaaaaaggccgcgttgctggcgtttttccataggctccgcccccctgacgagcatcacaaaaatcgacgctcaagtc agaggtggcgaaacccgacaggactataaagataccaggcgtttccccctggaagctccctcgtgcgctctcctgttccga ccctgccgcttaccggatacctgtccgcctttctcccttcgggaagcgtggcgctttctcatagctcacgctgtaggtatctcag ttcggtgtaggtcgttcgctccaagctgggctgtgtgcacgaaccccccgttcagcccgaccgctgcgccttatccggtaact atcgtcttgagtccaacccggtaagacacgacttatcgccactggcagcagccactggtaacaggattagcagagcgag gtatgtaggcggtgctacagagttcttgaagtggtggcctaactacggctacactagaagaacagtatttggtatctgcgctct gctgaagccagttaccttcggaaaaagagttggtagctcttgatccggcaaacaaaccaccgctggtagcggtggtttttttg tttgcaagcagcagattacgcgcagaaaaaaaggatctcaagaagatcctttgatcttttctacggggtctgacgctcagtg gaacgaaaactcacgttaagggattttggtcatgagattatcaaaaaggatcttcacctagatccttttaaattaaaaatgaa gttttaaatcaatctaaagtatatatgagtaaacttggtctgacagttaccaatgcttaatcagtgaggcacctatctcagcgat ctgtctatttcgttcatccatagttgcatttaaatttccgaactctccaaggccctcgtcggaaaatcttcaaacctttcgtccgatc catcttgcaggctacctctcgaacgaactatcgcaagtctcttggccggccttgcgccttggctattgcttggcagcgcctatc gccaggtattactccaatcccgaatatccgagatcgggatcacccgagagaagttcaacctacatcctcaatcccgatctat ccgagatccgaggaatatcgaaatcggggcgcgcctggtgtaccgagaacgatcctctcagtgcgagtctcgacgatcc atatcgttgcttggcagtcagccagtcggaatccagcttgggacccaggaagtccaatcgtcagatattgtactcaagcctg gtcacggcagcgtaccgatctgtttaaacctagatattgatagtctgatcggtcaacgtataatcgagtcctagcttttgcaaa catctatcaagagacaggatcagcaggaggctttcgcatgattgaacaagatggattgcacgcaggttctccggcggcttg ggtggagaggctattcggctatgactgggcacaacagacaatcggctgctctgatgccgccgtgttccggctgtcagcgca ggggcgtccggttctttttgtcaagaccgacctgtccggtgccctgaatgaactgcaagacgaggcagcgcggctatcgtg gctggcgacgacgggcgttccttgcgcggctgtgctcgacgttgtcactgaagcgggaagggactggctgctattgggcg aagtgccggggcaggatctcctgtcatctcaccttgctcctgccgagaaagtatccatcatggctgatgcaatgcggcggct gcatacgcttgatccggctacctgcccattcgaccaccaagcgaaacatcgcatcgagcgagcacgtactcggatggaa gccggtcttgtcgatcaggatgatctggacgaagagcatcaggggctcgcgccagccgaactgttcgccaggctcaagg cgtctatgcccgacggcgaggatctcgtcgtgacccacggcgatgcctgcttgccgaatatcatggtggaaaatggccgct tttctggattcatcgactgtggccgtctgggtgtggcggaccgctatcaggacatagcgttggctacccgtgatattgctgaag agcttggcggcgaatgggctgaccgcttccttgtgctttacggtatcgccgcgcccgattcgcagcgcatcgccttctatcgc cttcttgacgagttcttctgaccgattctaggtgcattggcgcagaaaaaaatgcctgatgcgacgctgcgcgtcttatactcc cacatatgccagattcagcaacggatacggcttccccaacttgcccacttccatacgtgtcctccttaccagaaatttatcctt 5 aaggtcgtttaaactcgactctggctctatcgaatctccgtcgtttcgagcttacgcgaacagccgtggcgctcatttgctcgtc gggcatcgaatctcgtcagctatcgtcagcttacctttttggca SEQ ID NO: 15 LAUDA-forward ggtggaaggaggcagaattg SEQ ID NO: 16 LAUDA-probe 10 cacgggcaccatgaa SEQ ID NO: 17 LAUDA-reverse gggcctgcttggcttttc

Claims

1. A viral plasmid comprising a recombinant gene expression cassette,the recombinant gene expression cassette comprising:a) a polynucleotide encoding a soluble tissue non-specific alkaline phosphatase (sTNAP) or a functional variant thereof;b) a polynucleotide encoding a regulatory element operatively linked to the polynucleotide of a);c) a polynucleotide encoding an Fc domain; andd) a polynucleotide encoding a hydroxyapatite binding domain;wherein the viral plasmid further comprises at least one inverted terminal repeat (ITR) from a virus of the family Parvoviridae.

2. The viral plasmid of claim 1, wherein the regulatory element of b) is a tissue specific promoter.

3. The viral plasmid of any one of the preceding claims, wherein the tissue specific promoter is a liver-specific promoter.

4. The viral plasmid of any one of the preceding claims, wherein the hydroxyapatite binding domain is selected from the group consisting of poly-aspartic acid and polyglutamic acid preferably wherein the poly-aspartic acid and the poly-glutamic acid comprise between six and fifteen continuous residues, preferably wherein the hydroxyapatite binding domain is decapeptide aspartic acid (D10).

5. The viral plasmid of any one of the preceding claims, wherein the polynucleotide a) comprises a nucleic acid sequence that is at least 80% identical to the nucleic acid sequence set forth in SEQ ID NO: 1.

6. The viral plasmid of any one of the preceding claims, wherein the polynucleotide a) encodes an amino acid sequence that is at least 70% identical to the amino acid sequence set forth in SEQ ID NO: 2.

7. The viral plasmid of any one of the preceding claims, wherein the polynucleotide c) comprises a nucleic acid sequence that is at least 70% identical to the nucleic acid sequence set forth in SEQ ID NO: 5.

8. The viral plasmid of any one of the preceding claims, wherein the at least one ITR is from an adeno-associated virus (AAV).

9. The viral plasmid of any one of the preceding claims, wherein the at least one ITR comprises a 5’ ITR and a 3’ ITR flanking the recombinant gene expression cassette.

10. The viral plasmid of any one of the preceding claims, wherein the recombinant gene expression cassette further comprisese) one or more miRNA binding sites.

11. The viral plasmid of any one of the preceding claims, wherein the one or more miRNA binding sites are recognised by a miR126 strand selected from the group consisting of miR126-3p and miR126-5p, preferably miR126-5p.

12. The viral plasmid of any one of the preceding claims, wherein the one or more miRNA binding sites comprises a nucleic acid sequence at least 70% identical to the nucleic acid sequence as set forth in SEQ ID NO: 9.

13. The viral plasmid of any one of the preceding claims, wherein the recombinant gene expression cassette further comprisesf) a polynucleotide comprising one or more 5’ intron sequences; and / org) a polynucleotide comprising one or more Woodchuck Hepatitis Virus posttranscriptional regulatory element (WPRE) sequences.

14. An isolated polynucleotide comprising the viral plasmid of any one of claims 1 to 13.

15. A recombinant virus comprising the recombinant gene expression cassette as defined in any one of claims 1 to 13 and a capsid.

16. The recombinant virus of claim 15, wherein the capsid is from a virus of the family Parvoviridae, preferably wherein the capsid is from a virus of the family Parvoviridae exhibiting liver tropism.

17. The recombinant virus of any one of claims 15 or 16, wherein the capsid is from AAV8.

18. A host cell comprising the viral plasmid of any one of claims 1 to 13, the isolated polynucleotide of claim 14, or the recombinant virus of any one of claims 15 or 16.

19. A pharmaceutical composition comprising the viral plasmid of any one of claims 1 to 13, the isolated polynucleotide of claim 14, the recombinant virus of any one of claims 15 to 17, or the host cell of claim 18, and optionally one or more excipients.

20. The viral plasmid of any one of claims 1 to 13, the isolated polynucleotide of claim 14, the recombinant virus of any one of claims 15 to 17, the host cell of claim 18, or the pharmaceutical composition of claim 19 for use as a medicament.

21. The viral plasmid of any one of claims 1 to 13, the isolated polynucleotide of claim 14, the recombinant virus of any one of claims 15 to 17, the host cell of claim 18, or the pharmaceutical composition of claim 19 for use in the treatment of pyrophosphate deposition diseases in a subject in need thereof, preferably the treatment increases mineralization in bone or dental tissue in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases and / or wherein the treatment increases the ratio of extracellular Pi to PPi in a subject suffering from pyrophosphate deposition diseases compared to an untreated subject suffering from pyrophosphate deposition diseases.

22. The viral plasmid, the isolated polynucleotide, the recombinant virus, the host cell, or the pharmaceutical composition for use according to any one of claims 20 or 21, wherein the pyrophosphate deposition disease is hypophosphatasia (HPP).

23. The recombinant virus for use according to any one of claims 20 to 22, wherein the recombinant virus is administered to a subject in need thereof at a dose of about 2 x 1012 to 2 x 1014 vg / kg, preferably about 2 x 1013 to 3 x 1013vg / kg.

24. The recombinant virus for use according to any one of claims 20 to 23, wherein the 5 recombinant virus is administered to a subject who has previously received enzyme replacement therapy (ERT) for hypophosphatasia.

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