CMTX1, the X-linked dominant form of CMT, is the second most common form of CMT and the first X-linked form of CMT, with 7% to 12%, and 50% of all CMT cases and X-linked cases, respectively (Boerkoel et al., 2002; Huttner et al., 2006; Ouvrier et al., 2007; Pareyson and Marchesi, 2009; Fridman et al., 2015). The gene discussed is GJB1; the disease is Charcot-Marie-Tooth disease.