Charcot-Marie-Tooth (CMT) disease is the most prevalent form of familial neuropathy. More than half of patients with CMT disease demonstrate an autosomal dominant pattern of inheritance of dysmyelinative neuropathy caused by overexpression of peripheral myelin protein 22, which results from a chromosome 17p12 duplication (CMT disease type 1A).1,2 The second most common are families with X-linked neuropathy caused by connexin 32 mutations (CMT disease type 1X); affected males in these families may show features of dysmyelination and axonopathy.1,3 The third most frequent category of patients with CMT disease are those with various myelin P0 mutations. Autosomal dominant (toxic gain of function) and recessive (loss of function) patterns of inheritance have been reported, and patients may show predominantly dysmyelination or mixed dysmyelination and axonopathy.1,4 Other, rarer, forms of CMT disease with either dominant or recessive inheritance patterns can cause axonopathy, myelinopathy, or a mixture of both. A comprehensive listing of CMT disease mutations is available (http://www.molgen.ua.ac.be/CMTMutations/default.cfm).