GJB1 and X-linked Charcot-Marie-Tooth disease type 1: Indeed, mutations in the human gene gap junction protein beta 1 (GJB1), which encodes Cx32, lead to the pathological phenotype of the X-chromosomal form of Charcot-Marie-Tooth (CMT1X or CMTX1), where inflammatory processes in peripheral nerves decrease conduction velocity of action potentials, leading to muscle atrophy (Bergoffen et al., 1993a; Fischbeck et al., 1996; Abrams et al., 2002).