For instance, Bello et al. performed a longitudinal study that categorized BMD patients into groups: deletions beginning at exon 45 ‘del 45’, ending on exon 51 ‘del 51’ or other mutations.S1 The ‘del 45’ group showed greater severity in almost every measure as compared with other BMD‐causing mutations and had lower levels of dystrophin protein. The gene discussed is DMD; the disease is Becker muscular dystrophy.