Charcot-Marie-Tooth disease is a group of disorders that affect the peripheral nerves, the nerves running from outside the brain and spine.
Alternative Names:
Progressive neuropathic (peroneal) muscular atrophy; Hereditary peroneal nerve dysfunction; Neuropathy - peroneal (hereditary); Hereditary motor and sensory neuropathy
Causes, incidence, and risk factors:
Charcot-Marie-Tooth is one of the most common inherited nerve-related disorders. Defects in at least 14 genes cause different forms of this disease.
The disease involves damage to the covering (myelin sheath) around nerve fibers. In some, the disease causes destruction of the myelin sheath. In others, the central (axon) portion of the nerve cell wears away.
Nerves that stimulate movement (the motor nerves) are most severely affected. The nerves in the legs are affected first and most severely.
Symptoms:
Symptoms usually begin between mid-childhood and early adulthood. They may include:
Foot drop (inability to hold foot horizontal)
Foot deformity (very high arch to feet)
Loss of lower leg muscle, which leads to skinny calves
Numbness in the foot or leg
"Slapping" gait (feet hit the floor hard when walking)
Later, similar symptoms may appear in the arms and hands, which may include a claw-like hand deformity.
Signs and tests:
A physical exam may show thickened nerve bundles under the skin of the legs. The stretch reflexes in the legs are absent. There is loss of muscle control and atrophy in the foot or leg. Lifting up the foot and toe-out movements will be difficult.
Genetic testing is available for most forms of the disease.
Review Date: 7/10/2007
Reviewed By: A.D.A.M. Editorial Team: Greg Juhn, M.T.P.W., David R. Eltz, Kelli A. Stacy. Previously reviewed by Brian Kirmse, MD, Mount Sinai School of Medicine, Department of Human Genetics, New York, NY. Review provided by VeriMed Healthcare Network (5/16/2007).
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Neurogenetics, Neuromuscular Disorders (e.g., ALS/Lou Gehrig's Disease)
