Peripheral myelin protein 22 p.Tll8M point mutation in a family with no clinical phenotypes of Charcot-Marie-Tooth disease

The peripheral myelin protein 22 ( PMP22 ) p.T118M variant has been detected in a number of families with Charcot-Marie-Tooth (CMT) disease. CMT disease is a neuropathy with clinical and genetic heterogeneity. The PMP22 gene encodes a protein called PMP22 , which is a major component of myelin in peripheral nervous system. We describe the c.353C>T p.T118M mutation in two cases with cerebral palsy (CP) detected by whole-exome sequencing. Direct sequencing revealed the p.T118M mutation in the father and in the sibling of the two cases; the mother carried the wild-type allele; and the p.T118M allele was heterozygous in all detected individuals. Collectively, the genetic analysis of the two cases with CP and the family described in this study showed no significant influence of the p.T118M variant on the CMT phenotypes. In agreement with previous studies, we conclude that the p.T118M variant can either be benign or cause partial loss of function, but can be disease-causing in certain conditions.