Recombinant FMR1 Constructs for AAV9-Mediated FMRP Restoration

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Solution Overview

Problem

There are currently no effective treatments for Fragile X Syndrome (FXS) and related disorders, which are caused by the loss of Fragile X Mental Retardation Protein (FMRP) due to epigenetic silencing of the FMR1 gene, leading to severe manifestations such as intellectual disability and autism.

Innovation Solution

Development of a therapeutic polynucleotide comprising a human endogenous FMR1 promoter fragment, human FMR1 isoform 7 sequence, and a 3′ regulatory element, delivered using an adeno-associated virus (AAV) vector, particularly AAV9, to restore FMRP production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a full mutation allele is present on the FMR1 gene, then epigenetic changes occur including methylation of cytosine nucleotides and histone modification, but this results in FMR1 silencing and absence of FMRP production

Engineering Contradiction:

Improvegene expression stabilityVSAvoidFMRP production

Core Design Contradiction:

ReliabilityVSQuantity of substance

Solution Approach 1:

The patent segments the FMR1 gene into essential functional components (promoter region, coding sequence, 3' UTR) and reconstructs a minimal functional unit that can be delivered via AAV vector. This segmentation allows bypassing the silenced full mutation allele while restoring essential FMRP production capabilities.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent introduces an AAV vector as an intermediary delivery system that carries the therapeutic FMR1 construct into target cells. This intermediary approach allows introduction of functional FMR1 sequences without directly confronting the epigenetically silenced endogenous allele, thereby restoring FMRP production despite the presence of the full mutation.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If no effective treatment is available for FXS, then current therapeutic options are limited, but developing gene therapy cassettes requires complex vector design and delivery systems

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoidgene therapy cassette design

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts only the essential functional elements of the FMR1 gene (promoter, coding sequence, 3' UTR) required for FMRP production, removing non-essential portions. This extraction creates a compact therapeutic cassette that fits within AAV packaging limits while maintaining therapeutic efficacy, thereby reducing design complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent optimizes parameters of the FMR1 construct including promoter strength, coding sequence integrity, and 3' UTR elements to achieve appropriate expression levels. These parameter adjustments ensure therapeutic efficacy while maintaining compatibility with AAV vector constraints, balancing effectiveness with design feasibility.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS20250242053A1Recombinant therapeutic FMR1 constructs and methods of treating fragile x syndrome and related disorders

Publication Date: 2025.07.31 THE UNIV COURT OF THE UNIV OF EDINBURGH

AI summary

Recombinant human FMR1 constructs and related methods for treating Fragile X syndrome and related disorders in a subject are provided.