Charcot Marie Tooth Disease

What is Charcot-Marie-Tooth disease?

Charcot Marie Tooth disease (CMT) is a common class of inheritable neurological disorders named for the physicians who discovered it. CMT is also known as “hereditary motor and sensory neuropathy (HMSN)” and “peroneal muscular atrophy.”

CMT is a class of peripheral neuropathies, meaning that it affects the peripheral nerves. The peripheral nerves are nerve fibers outside of the brain and spinal cord that feed into the motor and sensory areas of the body, such as the legs and arms.

What are the causes of Charcot-Marie-Tooth disease?

There are 80 different forms of CMT, each caused by a different gene mutation. The most common forms of CMT are inherited dominantly, meaning that they are passed down from generation to generation. These inherited gene mutations alter the structure and/or function of the peripheral nerves or their protective coating, the myelin sheath. Abnormal peripheral nerves may have trouble signaling to their target muscles throughout the body. They may also have trouble sending sensory information from the limbs back to the brain. Different forms of CMT cause different effects, but they all result in nerve degeneration of some sort.

What are the symptoms of Charcot-Marie-Tooth disease?

Different forms of CMT cause different effects, depending on which nerves are affected. Onset of symptoms is usually in adolescence or early adulthood and symptoms progress gradually. Symptoms may include, but are not limited to…

  • Muscle weakness
  • Atrophy in the extremities (feet, legs, hands, arms)
  • Reduced ability to feel heat, cold, pain
  • Occasional aching or burning sensations
  • Gradual hearing loss, deafness, loss of vision
  • Difficulty using fine motor skills and coordinating small movements
  • Pain, ranging in location and severity
  • Respiratory muscle weakness in rare cases

CMT oftentimes causes foot disorders due to the typical weakness that presents in the lower leg and foot muscles.

Symptoms specifically regarding the foot may include, but are not limited to…

  • Foot and lower leg muscle weakness
  • Balance difficulties
  • Foot drop (inability to raise the front part of the foot)
  • High-stepped gait
  • Frequent tripping or falling
  • High arches
  • Flat feet
  • Hammer toe (deformity in which the end of the toe bends downward like a claw)
  • Difficulty flexing the foot
  • Difficulty walking on the heel of the foot
  • Wasting away of the leg muscles, skinny calves
  • Difficulty coordinating toe and foot movements
  • Foot and lower leg pain

Foot numbness

How is Charcot-Marie-Tooth disease treated?

CMT is a chronic condition, but most forms of the disease do not shorten life expectancy. Individualized physical and occupational therapy programs are often recommended for symptom management. These programs may include…

  • Muscle strength training to delay and/or reduce muscle atrophy
  • Stamina training to diminish muscle fatigue
  • Stretching (muscle and ligament) to prevent or reduce deformities
  • Moderate, low-impact aerobic exercise (ex. biking, swimming) to improve overall cardiovascular health without putting too much stress on the feet and legs
  • Orthopedic devices (ex. ankle braces, shoe inserts) to use on an everyday basis for mobility and injury prevention
  • Wheelchairs can be utilized, though the lower leg muscles rarely weaken to this extent
  • Referral for orthopedic surgery to handle severe deformities and/or damage

Sources Cited