PMP22 and Charcot-Marie-Tooth disease type 1A: On the other hand, hereditary motor and sensory neuropathy, known as Charcot–Marie–Tooth (CMT) disease, arises from mutations in various genes.4,5 Until now, over 100 genes have been identified with a causative role in CMT disease (http://neuromuscular.wustl.edu/time/hmsn.html), among which peripheral myelin protein 22 (PMP22) is the most common causative gene for CMT1, primarily responsible for myelin adhesion and maintenance.6 Duplication in the PMP22 gene leads to CMT type 1A (CMT1A), presenting reduced nerve conduction velocity, usually evident in the first decade of life.