Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. It is described as a group of conditions in which damage to the peripheral nerves (outside of the brain and spinal cord) results in muscle weakness and reduced sensation in the legs, feet & hands.
It is also known as hereditary motor and sensory neuropathy (HMSN) or peroneal muscular atrophy. The disease is named for the three physicians who first identified it in 1886 – Jean-Martin Charcot and Pierre Marie in Paris, France and Howard Henry Tooth in Cambridge, England.
CMT leads to deterioration in the peripheral nerves. Peripheral nerves are in the limbs and are composed of motor and sensory nerve fibres. It is only the peripheral nervous system that is affected by CMT. Peripheral nerves are made up of axons wrapped in insulating material known as myelin. If the myelin becomes damaged, the signals tend to be conducted more slowly than normal. If the axons are damaged, the speed of conduction is normal but the strength of the signal is reduced.
The various types and sub-types of CMT are classified on the basis of the genes that are mutated, the way the disease is inherited, the speed of nerve conduction, the age of disease onset, and the severity level of the condition, the clinical symptoms, and the site of peripheral nerve damage.
There are generally 2 types of CMT:
The different types of CMT disease are CMT1, CMT2, CMT3, CMT4, CMTX, and DI-CMT. CMT1 is the most common type of CMT, accounting for about two-thirds of all cases.
A typical feature includes weakness of the foot and lower leg muscles, which may result in foot drop and a high-stepped gait with frequent tripping or falls. Foot deformities, such as high arches and hammertoes can present (a condition in which the middle joint of a toe bends upwards).
At Later stages, weakness and muscle atrophy (wasting) may occur in the hands, resulting in difficulty with carrying out fine motor skills (the coordination of small movements usually in the fingers, hands, wrists, feet, and tongue).
Onset of symptoms is most often in adolescence or early adulthood, but some individuals develop symptoms in mid-adulthood. Progression of symptoms is gradual. Pain can range from mild to severe, and some people may need to rely on foot or leg braces or orthotics to maintain mobility. Although in rare cases, individuals may have respiratory muscle weakness, CMT is not considered a fatal disease have a normal life expectancy.
Diagnosis of CMT begins with a standard medical history, family history, and neurological examination. During the neurological examination a Specialist/Neurological Physio will look for evidence of muscle weakness in the individual’s arms, legs, hands, and feet, decreased muscle bulk, reduced tendon reflexes, and sensory loss. Any evidence of foot deformities, such as high arches, hammertoes, inverted heel, or flat feet is noted. A specific sign that may be found in people with CMT1 is nerve enlargement that may be felt or even seen through the skin. If CMT is suspected, the GP/FCP may order electro-diagnostic tests. This testing consists of two parts: nerve conduction studies and electromyography (EMG).
Genetic testing is available for some types of CMT and results are usually enough to confirm a diagnosis. In addition, genetic counselling is available to assist individuals in understanding their condition and plan for the future. Recently, skin biopsy has been used to study unmyelinated and myelinated nerve fibres in a minimally invasive way, but their clinical use in CMT has not yet been established.
Our Physiotherapists understand the difficulties experienced by people with CMT and our aim is to help promote the independence of patients with CMT. The Physiotherapists based at Pure will follow an exercise-based, hands on treatment protocol. This may consist of the following:
Exercises & Stretching for CMT – click here.