Spectrum of DMD gene mutations in 507 patients: a retrospective genotype-phenotype study using next-generation sequencing.

BACKGROUND

Duchenne muscular dystrophy (DMD) is caused by mutations in the DMD gene, but comprehensive analyses of mutational patterns and clinical correlations remain limited.

OBJECTIVE

To characterize the DMD mutational spectrum and its clinical implications in a large Asian cohort.

METHODS & SETTINGS: A retrospective genetic analysis of 507 unrelated male DMD/Becker muscular dystrophy patients was conducted at Hunan Children's Hospital (2018-2021). Multiplex ligation-dependent probe amplification (MLPA) and next-generation sequencing (NGS) were employed for comprehensive variant detection. Variants were classified per ACMG/AMP guidelines.

RESULTS

Exon deletions predominated (64.9%), followed by small mutations (26.0%) and duplications (9.1%). Nonsense mutations were the most frequent small variant (16.0%). Domain analysis revealed mutations clustered in the Central Rod Domain (CRD; exons 45-55). The Carboxy-Terminal Domain (CTD) was associated with the most severe phenotype (earliest loss of ambulation, P < 0.05 vs. Actin-Binding Domain [ABD] or CRD). Exon 53 skipping was applicable in 39.39% of eligible patients. De novo mutations accounted for 7.9% (40/507) of cases. Epilepsy comorbidity occurred in 1.34% (6/448) of DMD patients.

CONCLUSION

This study delineates the DMD mutational landscape in a Chinese cohort, highlighting domain-specific phenotypic severity (CTD > ABD > CRD) and identifying exon 53 as the primary therapeutic target for exon skipping. These findings enhance prognostic precision and guide targeted therapeutic strategies.