Charcot-Marie-Tooth disease (CMT)

Charcot-Marie-Tooth disease (CMT) is a genetic disorder that affects the peripheral nervous system. CMT is a form of genetic, hereditary motor-sensitive neuropathy. It is one of the rare diseases in which CMT affects between 1/7,000 and 1/5,000 of children born alive.

It leads to progressive weakness and numbness in the muscles, usually affecting the feet and legs first, and later possibly also the hands and arms. CMT is one of the most common hereditary diseases of the peripheral nerves and occurs in various forms. It is named after the doctors Jean-Martin Charcot, Pierre Marie and Henry Tooth, who described the disease at the end of the 19th century.

CMT is caused by mutations in various genes that are responsible for the formation of nerve fibres and myelin (the protective layer of nerves).

The symptoms of Charcot-Marie-Tooth usually develop slowly and typically begin in childhood or young adulthood. However, they can also occur later in life. The most common symptoms include

• Weakness and atrophy of the muscles, especially in the lower extremities (feet and legs) and later also in the hands and arms.
• Loss of muscle mass, mainly affecting the lower legs, which can lead to a «fox foot» deformity (pes cavus) and a weak gait.
• Numbness or tingling in the affected limbs because the nerves can no longer transmit the signals correctly.
• Difficulty walking, including instability and frequent stumbling.
• Changes in the shape of the foot, such as a high arch or dropping of the foot (drop foot).
• Pain in the affected muscles and nerves.

CMT usually progresses slowly and symptoms worsen over a period of years. However, most people with CMT have a normal life expectancy and the disease does not affect mental abilities. The course of the disease can vary greatly depending on which subtype of CMT is present and how severely the nerves are damaged.

The diagnosis of CMT is usually made using a combination of clinical examination, family history, electromyography (EMG), nerve conduction velocity testing and genetic testing.

There is currently no cure for CMT, but there are measures that can be taken to alleviate the symptoms and slow the progression of the disease:

• Physiotherapy: This is one of the most important treatments to maintain muscle strength, promote mobility and improve balance. It also helps to prevent stiffness in the joints.
• Occupational therapy: Occupational therapists help to make everyday activities such as dressing, writing or eating easier by recommending adaptive equipment and techniques.
• Orthopaedic aids: Splints, foot orthoses or special shoes can help to improve stability and support the foot. In some cases, surgery is also necessary to correct deformities.
• Pain management: Painkillers or other forms of therapy such as transcutaneous electrical nerve stimulation (TENS) can be used to relieve pain and numbness.
• Surgical interventions: In some cases, surgery may be required to correct foot deformities or improve function in daily life.

The prognosis for people with Charcot-Marie-Tooth varies depending on the severity and form of the disease. Most people can lead a normal life, although they may need additional support to maintain their mobility and independence. It is important to recognise symptoms early and take measures to control symptoms.

Overall, Charcot-Marie-Tooth disease is a chronic but slowly progressing disease that can enable a good quality of life with appropriate treatment and support.