The purpose of this study was the identification of new mutations of the connexin 32 (CX32) gene in CMTX families. We report six new mutations of the CX32 gene including two medium sized (29 and 18 bp) deletions. The clinical phenotype is consistent with CMT peripheral neuropathy in all patients. Four families show both male and female patients, with more severe symptoms in males. The disease is asymptomatic in females in two families. The clinical deficit in CMTX families Nos 1, 2 and 4 with missense mutations of the CX32 gene was mild or moderate. Severe weakness of the feet and hands was present in CMTX family No. 5 with a G insertion and family No. 6 with a 29 bp deletion in the carboxyl terminal region of the CX32 gene. Most likely the severe clinical impact in those families was related to frame shift and premature termination of the protein.