MPZ and Charcot-Marie-Tooth disease: However, some CMT subtypes, such as those with GJB1 or MPZ mutations, can exhibit these electrophysiological features (Ginsberg et al., 2004, Gutierrez et al., 2000, Marques et al., 2010, Michell et al., 2009, Miki et al., 2013, Tabaraud et al., 1999).