GJB1 and X-linked Charcot-Marie-Tooth disease type 1: Consistent with this, mutations of several amino acid residues located within this site (M34, V38, A40, and E41) are involved in the onset of the X-linked Charcot-Marie-Tooth (CMT1X), a Cx32-linked connexinopathy [5], highlighting the functional importance of site M in channel function under physiological and pathophysiological conditions.