Charcot-Marie-Tooth Disease and Related Inherited Myelin Disorders Molecular Genetics and Implications for Gene Therapy

Charcot-Marie-Tooth disease (CMT) is an inherited disorder of the peripheral nerves, which involves slowly progressive weakness and atrophy of the distal muscles (Charcot and Marie, 1886; Tooth, 1886). CMT is a type of hereditary motor and sensory neuropathy that exhibits both clinical and genetic heterogeneity (Dyck et al., 1993; Lupski et al., 1991a). Clinical features include initial weakness of the intrinsic foot and distal leg muscles, which lead to foot deformities and gait abnormalities. Later in the course of the disease, variable progressive weakness of the hands may occur (Dyck et al. 1993; Lupski et al., 1991a). CMT constitutes the most common inherited peripheral neuropathy with an estimated population frequency of 1:2500 (Skre, 1974). Studies on the molecular genetics of CMT have provided a wealth of information in recent years, which was facilitated by parallel developments in mouse models of the disease. This brief review will summarize the current findings, paying particular attention to CMT type 1A, which is the major form of the disease. The molecular findings on CMTIA have revealed a novel mutational mechanism for an autosomal dominant human disorder. Furthermore, the gene responsible for CMTIA has been shown to be involved in two related peripheral neuropathies as well. The collective findings have furthered our understanding of the molecular bases of primary inherited peripheral neuropathies and have provided useful insights on the prospective development of strategies for gene therapy of CMT and related disorders.