Dystrophin (DMD) gene exon 1 deletion junction (DMD exon 1 del junction)

The DMD gene exon 1 deletion junction is a specific genomic sequence created by the loss of the first exon in the dystrophin (DMD) gene, a mutation typically associated with severe Duchenne muscular dystrophy (DMD) (MedlinePlus, 2024). This junction serves as a precise molecular target for next-generation genetic therapies, such as CRISPR/Cas9-mediated gene editing, which aim to restore the production of the dystrophin protein (Nelson et al., 2016). Dystrophin is a vital structural protein that anchors the internal cytoskeleton of muscle fibers to the surrounding extracellular matrix, protecting muscle cells from mechanical stress during contraction (UniProt P11532). When exon 1 is deleted, the primary promoter and translational start site are often lost, leading to a failure in protein synthesis and subsequent muscle degeneration (NIH/GARD, 2023). Therapeutic interventions targeting this junction seek to re-establish a functional reading frame or utilize alternative internal promoters to produce a shortened but functional version of dystrophin. Beyond therapy, the junction sequence is used as a diagnostic biomarker to identify specific patient populations and monitor the precision of gene-editing tools. Safety considerations for targeting this site include the risk of off-target DNA cleavage and the potential for immune reactions against the delivery vehicles or the editing machinery itself. Successful editing of this junction could potentially convert a severe DMD phenotype into a milder Becker muscular dystrophy (BMD) phenotype by restoring some level of dystrophin function.

Other names

DMD exon 1 breakpointDystrophin exon 1 deletion siteDMD promoter-exon 1 junction

Genomic restoration of the dystrophin reading frame or promoter activity