Few malignant melanoma (MM) susceptibility genes have been described in the literature so far, with only two high-penetrance genes mutated in 20-40% of familial cases (Cyclin-dependent kinase inhibitor 2 (CDKN2A) and Cyclin-dependent kinase 4 (CDK4)) [1-3]. The gene discussed is CDK4; the disease is Miyoshi myopathy.