Tuesday 20 December 2011
Charcot-Marie-Tooth (CMT) disease-2A1 results from mutation in the KIF1B gene (MIM.605995) on chromosome 1p36.2.
A second form of CMT2A mapping to chromosome 1p36.2, CMT2A2 (MIM.609260), results from mutation in the MFN2 gene (MIM.608507).
Charcot-Marie-Tooth disease constitutes a clinically and genetically heterogeneous group of hereditary motor and sensory neuropathies.
On the basis of electrophysiologic criteria, CMT is divided into 2 major types: - type 1, the demyelinating form, characterized by a slow motor median nerve conduction velocity (NCV) (less than 38 m/s),
type 2, the axonal form, with a normal or slightly reduced NCV.
Distal hereditary motor neuropathy (dHMN), also known as spinal CMT, is a third type of CMT characterized by normal motor and sensory NCV and degeneration of spinal cord anterior horn cells.
CMT1B (MIM.118200) and CMT1A (MIM.118220): autosomal dominant slow nerve conduction types of Charcot-Marie-Tooth disease.
CMT4A (MIM.214400) and CMTX1 (MIM.302800): autosomal recessive and X-linked forms of Charcot-Marie-Tooth disease.
Several forms of axonal CMT neuropathies caused by mutations in different genes or at different loci have been described: