DMD and neuromuscular disease caused by qualitative or quantitative defects of dystrophin: The phenotypic heterogeneity in dystrophinopathies likely relies on individual differences in genetic background and on the variety of mutation profiles within the dmd gene, which may lead to the sole loss of brain full-length dystrophin (Dp427) or to a cumulative loss of shorter dystrophins encoded by distinct internal promoters, such as Dp140 and Dp71 [13].