We thus generated transgenic mouse lines with BACs containing human GJB1 genes expressing either the mutation G12S, observed in non-related CMTX families and affecting trafficking of Cx32 (G12S) (Yum et al., 2002) or the mutation S26L, affecting connexon activity (S26L) (Yoshimura et al., 1996; Oh et al., 1997). Here, GJB1 is linked to X-linked Charcot-Marie-Tooth disease.