Charcot-Marie-Tooth type X: Unusual phenotype of a novel CX32 mutation

Background: X-linked Charcot-Marie-Tooth disease (CMTX), caused by mutations in the gene encoding connexin32, is the second most common form of inherited demyelinating neuropathy, next to CMT 1A, and accounts for 10-20% of all hereditary demyelinating neuropathies. Aims of the study: To describe clinical and electrophysiological data of an Italian family carrying a novel mutation in the Cx32 gene. Patients and methods: Clinical, electrophysiological, and genetic findings of three patients carrying the Ser128Leu mutation in the intracellular domain of the Cx32 gene were reported. Brain MRI studies were also performed. Results: In our family the disease was characterized by a moderate-to-severe polyneuropathy affecting similarly males as well females. In the proband the phenotype was quite unusual in terms of late-onset, rapidity of evolution and severity. Abnormal brain MRI in association with CNS symptoms were also observed. Both sons had also clinical evidence of CNS involvement. Conclusions: The Ser128Leu mutation in the Cx-32 gene is a novel substitution, which has not been reported so far. This novel mutation could be added to the group of Cx-32 mutations with CNS phenotypes. The identification of new CMTX causing mutations is a crucial step for carrier detection and pre-symptomatic diagnosis.