Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders, affecting approximately 1 in 2,500 people in the United States. CMT, also known as hereditary motor and sensory neuropathy (HMSN) or peroneal muscular atrophy, comprises a group of disorders caused by mutations in genes that affect the normal function of the peripheral nerves. The peripheral nerves lie outside the brain and spinal cord and supply the muscles and sensory organs in the limbs. A typical feature includes weakness of the foot and lower leg muscles, which may result in foot drop and a high-stepped gait with frequent tripping or falls. Foot deformities, such as high arches and hammertoes (a condition in which the middle joint of a toe bends upwards), are also characteristic due to weakness of the small muscles in the feet. In addition, the lower legs may take on an "inverted champagne bottle" appearance due to the loss of muscle bulk. Later in the disease, weakness and muscle atrophy may occur in the hands, resulting in difficulty with fine motor skills. Some patients experience pain, which can range from mild to severe.
There is no cure for CMT, but physical therapy, occupational therapy, braces and other orthopedic devices, and orthopedic surgery can help patients cope with the disabling symptoms of the disease. In addition, pain-killing drugs can be prescribed for patients who have severe pain.
Onset of symptoms of CMT is most often in adolescence or early adulthood, however presentation may be delayed until mid-adulthood. Progression of symptoms is very gradual. The degeneration of motor nerves results in muscle weakness and atrophy in the extremities (arms, legs, hands, or feet), and the degeneration of sensory nerves results in a reduced ability to feel heat, cold, and pain. There are many forms of CMT disease. The severity of symptoms is quite variable in different patients and some people may never realize they have the disorder. CMT is not fatal and people with most forms of CMT have a normal life expectancy.
Prepared by the National Institutes of Health