In our cohort, mutations in epigenes previously described in MM (ARID1A, DNMT3A, KDM5C, KMT2B and KMT2C) [5,7,8,15,22,23,24] as well as in novel epigenetic regulators (e.g., KDM5A, KMT2A, KMT2D, PRDM9 and PBRM1) appeared when the disease progressed. The gene discussed is KMT2C; the disease is Miyoshi myopathy.