Duplications of the DMD gene encoding dystrophin are rare and represent a real therapeutic challenge. An American team compiled the clinical and biological data of 66 patients with this relatively uncommon genotype:
- 61% of them had a DMD-like phenotype, 30% a Becker-like phenotype and 9% an intermediate phenotype,
- 3/4 of them were treated with long-term corticosteroids,
- overall, their evolutionary trajectory differed markedly from that of the historical cohort of DMD patients.
These data will be useful for conceptualizing future therapeutic trials.