GJB1 and Charcot-Marie-Tooth disease: Previous studies showed that about 60% of CMT patients received a definitive diagnosis by genetic testing, and over 90% of genetically diagnosed patients show an alteration in one of the following four genes: Peripheral Myelin Protein 22-kDa (PMP22), Gap Junction Beta 1 (GJB1), Myelin Protein Zero (MPZ), and Mitofusin 2 (MFN2) [2,16,17].