Charcot-Marie-Tooth disease encompasses a group of disorders called hereditary sensory and motor neuropathies that damage the peripheral nerves. Peripheral nerves connect the brain and spinal cord to muscles and to sensory cells that detect sensations such as touch, pain, heat, and sound. Damage to the peripheral nerves that worsens over time can result in alteration or loss of sensation and wasting (atrophy) of muscles in the feet, legs, and hands.
Charcot-Marie-Tooth disease can be caused by mutations in many different genes. These genes provide instructions for making proteins that are involved in the function of peripheral nerves in the feet, legs, and hands. The gene mutations that cause Charcot-Marie-Tooth disease affect the function of the proteins in ways that are not fully understood; however, they likely impair axons, which transmit nerve impulses, or affect the specialized cells that produce myelin. In most cases, longer nerves that transmit impulses to the appendages of the body are more likely to be affected. As a result, peripheral nerve cells slowly lose the ability to stimulate the muscles in the feet, legs, and eventually the hands, and to transmit sensory signals from these appendages to the brain. Different mutations within a single gene may cause signs and symptoms of differing severities or lead to different types of Charcot-Marie-Tooth disease.
Charcot-Marie-Tooth disease is the most common inherited disorder that involves the peripheral nerves, affecting an estimated 150,000 people in the United States. It occurs in populations worldwide with a prevalence of about 1 in 3,300 individuals.
The pattern of inheritance varies with the type of Charcot-Marie-Tooth disease. CMT1, most cases of CMT2, and most intermediate forms are inherited in an autosomal dominant pattern. This pattern of inheritance means that one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one affected parent. Each of the children of an affected parent has a 50 percent chance of inheriting the disorder.
Published Date: October 01, 2018Published By: National Institutes of Health