NSD2 and Wolf-Hirschhorn syndrome: Mutation of H3K36 trimethyltransferase WHSC1 gene (Wolf–Hirschhorn Syndrome candidate 1, also known as NSD2) is the major cause of Wolf–Hirschhorn syndrome (WHS), characterized by developmental defects including growth delay, mental retardation, short stature, radioulnar synostosis and mesomelic limb shortness, and craniofacial abnormalities (Bergemann et al., 2005; Mazzeu et al., 2007).