Approximately 15–20% of MM patients carry a translocation in the chromosome 4 (t(4;14)) that puts NSD2 expression under the control of the immunoglobulin heavy chain locus, leading to its overexpression, and a consequent global increase in H3K36me2, coupled with a global H3K27me3 decrease through EZH2 inhibition [16,17,48]. The gene discussed is NSD2; the disease is Miyoshi myopathy.