Mournetas et al. used myoblasts from three DMD patients with in-frame duplication exons 3 to 26, out-of-frame deletion exons 8 to 43, or stop exon 7 c mutations, all of which disrupt the Dp427 but not the Dp71 isoform, whereas the DMD-R3381X mutation in our study affects both isoforms. This evidence concerns the gene DMD and Duchenne muscular dystrophy.