Charcot-Marie-Tooth disease is a group of disorders that affect the peripheral nerves, the nerves running from outside the brain and spine.

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 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)
• Weakness of the hips, legs, or feet

Later, similar symptoms may appear in the arms and hands, which may include a claw-like hand deformity.

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.

A muscle biopsy or nerve biopsy may confirm the diagnosis. Nerve conduction tests are often done to tell the difference between different forms of the disorder.

Genetic testing is available for most forms of the disease.

There is no known cure. Orthopedic surgery or equipment (such as braces or orthopedic shoes) may make it easier to walk.

Physical and occupational therapy may help maintain muscle strength and improve independent functioning.

Charcot-Marie-Tooth disease slowly gets worse. Some parts of the body may become numb, and pain can range from mild to severe. Eventually the disease may cause disability.

• Progressive inability to walk
• Progressive weakness
• Injury to areas of the body that have decreased sensation

Call for an appointment with your health care provider if there is persistent weakness or decreased sensation in the feet or legs.

Genetic counseling and testing is advised if there is a strong family history of the disorder.