A rapidly progressive dHMN in a 15-year-old boy was due to the de novo previously reported c.1126A>G, p.(Met376Val) mutation in MFN2 (family 12).11 The heterozygous c.2119C>T p.(Arg707Trp) MFN2 mutation was found in a 70- year-old man with late-onset dHMN (family 13).12 The gene discussed is MFN2; the disease is distal hereditary motor neuropathy.