Charcot-Marie-Tooth diseases involve damage to nerves (neuropathy), usually from loss of the electrical insulation (myelin) around nerve fibers. All nerves are affected, but motor nerves (the nerves that stimulate movement) are most severely affected.

The nerves in the legs are affected first and most severely. Symptoms usually begin between mid-childhood and early adulthood. The disorder is inherited, with autosomal dominant, autosomal recessive as well as X-linked recessive inheritance patterns. At least four genes have been discovered to be the cause of this group of diseases.

Charcot-Marie-Tooth disease causes destruction of the myelin sheath in some people. In other people, the central (axon) portion of the nerve cell degenerates.

The disorder most commonly affects the nerves to the feet and legs, most significantly the peroneal nerve. The damage is slowly progressive, usually beginning with foot drop and progressing up the legs. There is a loss of muscle control and muscle tone, and eventual loss of muscle mass caused by lack of nervous stimulation to the muscles.

• Weakness (decreased muscle strength) of the hips, legs, or feet
• "Slapping" gait (the feet hit the floor hard when walking)
• Foot drop (inability to hold foot horizontal)
• Foot deformity (very high arch to feet)
• Progressive leg deformity
• "Stork leg" appearance (loss of lower leg muscle mass leading to skinny calves)
• Numbness in the foot or leg

• A muscle biopsy or nerve biopsy may confirm the diagnosis.
• Nerve conduction tests are often performed to distinguish axonal from demyelinating forms of the disorder.
• Genetic testing is available for most forms of the disease.

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