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DMD genotype correlations from duchenneConnect Endogenous exon skipping is a factor in prolonged ambulation for individuals with a defined mutation sub-type

Antisense oligonucleotide (AON) mediated exon skipping is an emerging therapeutic for individuals with Duchenne muscular dystrophy (DMD). Skipping of exons adjacent to common exon deletions in DMD using AONs can produce in-frame transcripts and functional protein. Targeted skipping of DMD exons 8, 44, 45, 50, 51, 52, 53, and 55 are predicted to benefit 47% of affected individuals. We observed a correlation between mutation subgroups and age at loss of ambulation in DuchenneConnect, a large database of phenotypic and genetic data for DMD (N = 765). Males amenable to exon 44 (N = 74) and exon 8 skipping (N = 18) showed prolonged ambulation compared to other exon skip groups and nonsense mutations (P = 0.035 and P < 0.01, respectively). In particular, exon 45 deletions were associated with prolonged age at LOA relative to the rest of the exon 44 skip amenable cohort and other DMD mutations. Exon 3-7 deletions also showed prolonged ambulation relative to all other exon 8 skippable mutations. Cultured myotubes from DMD patients with deletions of exons 3-7 or exon 45 showed higher endogenous skipping than other mutations, providing a potential biological rationale for our observations. These results highlight the utility of aggregating phenotypic and genotypic data for rare pediatric diseases to reveal progression differences, identify potentially confounding factors and probe molecular mechanisms that may affect disease severity. This article is protected by copyright. All rights reserved.

Citation

Wang, R. T., Barthelemy, F., Martin, A. S., Douine, E. D., Eskin, A., Lucas, A., ... Nelson, S. F. (2018). DMD genotype correlations from duchenneConnect: Endogenous exon skipping is a factor in prolonged ambulation for individuals with a defined mutation sub-type. Human Mutation. DOI: 10.1002/humu.23561

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