Four novel connexin 32 mutations in X-linked Charcot-Marie-Tooth disease. Phenotypic variability and central nervous system involvement

Charcot-Marie-Tooth (CMT) disease, the most common hereditary neuropathy, is clinically and genetically heterogeneous. X-linked CMT (CMTX) is usually caused by mutations in the gap junction protein b 1 gene (GJB1) coding for connexin 32 (Cx32). The clinical manifestations of CMTX are characterized by significant variability, with some patients exhibiting central nervous system (CNS) involvement. We report four novel mutations in GJB1, c.191G > A (p.Cys64Tyr), c.508G > T (p.Val170Phe), c.778A > G (p.Lys260Glu) and c.300C > G (p.His100Gln) identified in four unrelated Greek families. These mutations were characterized by variable phenotypic expression, including a family with the Roussy-Lévy syndrome, and three of them were associated with mild clinical CNS manifestations.