Mutations in LMNA were initially identified as the cause of autosomal dominant Emery-Dreifuss muscular dystrophy with clinical features nearly identical to X-linked Emery-Dreifuss muscular dystrophy caused by emerin (EMD) mutations.47 Mutations in LMNA appear to be common in patients with DCM with an associated skeletal myopathy. The gene discussed is LMNA; the disease is X-linked Emery-Dreifuss muscular dystrophy.