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14 | InTouch AUTUMN 2026 WHAT IS CHARCOT-MARIE-TOOTH DISEASE? forms. Some subtypes are associated with additional features, such as scoliosis, hearing loss, vocal cord involvement or cataracts. CMTX CMTX is inherited in an X-linked manner and is most commonly caused by mutations in the GJB1 gene. Males are usually more severely affected, while females may have milder symptoms or, in some cases, no noticeable symptoms. A note on CMT3 (Dejerine-Sottas syndrome) CMT3 was historically used to describe a particularly severe, early-onset form of CMT, typically beginning before three years of age and associated with delayed motor milestones and skeletal deformities. We now understand that several different genes can cause this phenotype and these cases are more accurately classified as CMT1 or CMT4, depending on whether the condition is inherited in a dominant or recessive pattern. What are the features of Charcot-Marie-Tooth Disease? 1. A high arched foot (called “pes cavus”) is usually one of the first signs of this disorder, although in some instances extremely flat feet (“pes planus”) are seen in CMT. Hammer toes (a condition in which the middle joint of a toe bends upwards) are common as well. As the disease progresses, these structural foot deformities can become more pronounced. 2. The progressive muscle wasting in the lower legs lead to an “inverted champagne bottle” appearance, and problems with walking, running, and balance will be noticed. Ankle weakness and sprains are common, and many patients develop foot drop. To avoid tripping, patients with foot drop raise their knees unusually high, resulting in the high “steppage” gait associated with CMT. In some patients, muscle weakness may also occur in the upper legs. 3. Later in the course of the disease, hand function may become affected. Progressive atrophy of the thenar muscle and the small muscles in the hand results in weakening or loss of the opposable pinch, and tasks requiring manual dexterity become difficult. 4. Patients may have problems holding pens and pencils, buttoning clothing, grasping zipper pulls, and turning doorknobs. Many people benefit from occupational therapy which helps people accomplish the tasks of daily living with the use of assistive devices. 5. The loss of nerve function is often accompanied by tingling and burning sensations in the hands and feet. This usually causes little more than mild discomfort, but some people experience significant neuropathic pain and may require medication to control it. Continued from previous page. 6. Loss of nerve function in the extremities can also result in sensory loss. The sense of touch is diminished, as is the ability to perceive changes in temperature, and patients may unknowingly injure themselves. They can be unaware of having developed ulcers of the feet or of cuts or burns on the hands. Sensory loss in CMT patients may also be associated with dry skin and hair loss in the affected areas. In rare cases, sensory loss can be associated with hearing impairment. 7. Many patients are very sensitive to the cold or even to slightly cooler temperatures. CMT results in the loss of insulating muscle mass, which, combined with reduced muscular activity and circulation, can leave patients with persistently cold hands and feet. Impairment of the normal circulatory process can also result in swelling (oedema) of the feet and ankles. 8. Deep-tendon reflexes, such as the knee jerk reaction, are reduced or absent in many patients, and this is of diagnostic importance. Some people with CMT also have tremor (usually of the hands), and the combination of tremor and CMT is sometimes referred to as Roussy-Levy syndrome (most often associated with PMP22 duplication / CMT1A). CMT results in the loss of insulating muscle mass, which, combined with reduced muscular activity and circulation, can leave patients with persistently cold hands and feet.