Summary
Charcot-Marie-Tooth disease, type 4G (CMT4G) is a demyelinating CMT peripheral sensorimotor polyneuropathy identified in Bulgarian, Romanian, French, and Spanish Gypsies and is also referred to as hereditary motor and sensory neuropathy-Russe (HMSNR). Onset occurs between 8 and 16 years of age with distal lower limb weakness, followed by distal upper limb involvement with a more variable age of onset of between 10 and 43 years. Sensory loss is also a prominent feature. Motor nerve conduction velocities are moderately reduced and the threshold for electrical nerve stimulation is increased. Nerve biopsies reveal a loss of large myelinated fibers, reduced thickness of the myelin sheath and profuse regenerative activity. CMT4G is transmitted in an autosomal recessive manner. The disease-causing gene has not yet been identified but linkage analysis and recombination mapping have led to identification of a small interval on 10q23.2.
Expert reviewer(s)
- Dr Carmen ESPINÓS
- Pr Francesc PALAU
Last update: January 2009