GJB1 and X-linked Charcot-Marie-Tooth disease type 1: X-linked Charcot-Marie-Tooth (CMT) disease (CMT1X), associated with over 400 different mutations in the GJB1 gene, is one of the commonest forms of inherited neuropathies (http://www.molgen.ua.ac.be/CMTMutations/) [8, 28].