Tibial muscular dystrophy (TMD), also called Udd distal dystrophy, is a type of muscular dystrophy affecting the muscles of the ankle and progressing up to the muscles of the tibia or shinbone in the lower leg.

TMD is inherited in an autosomal dominant manner and caused by mutations in the TTN gene that contain the information necessary to make a protein called titin. The mutations lead to the production of faulty titin protein, affecting the ability of muscles to contract, leading to muscle weakness and wasting over time.

Symptoms of TMD usually start around age 35 and usually progress slowly. Although walking may not be severely impaired, patients with TMD might find it difficult to move their feet up and down and to walk on their heels.

Like most other muscular dystrophies, there is currently no cure for TMD. Management of symptoms includes physiotherapy and occupational therapy to improve muscle strength and minimize the risk of injury. In more severe cases, using leg braces or wheelchairs to aid in mobility may be necessary.

Physiotherapy and occupational therapy

Physiotherapy can help maintain muscle mass and enhance the range of motion of the lower limbs. It is important to devise a safe exercise regimen in consultation with a physiotherapist as some forms of exercise can be harmful. Stretching exercises can help minimize muscle freezes (contractures).

Occupational therapy can help patients adapt to daily activities at home and at work in a manner that minimizes the risk of injury. The occupational therapist may suggest changes in the work area or give instructions about using leg braces while performing certain tasks.

Orthoses

TMD affects the muscles of the lower leg, which can make walking difficult. Some TMD patients experience a condition known as foot drop, in which lifting the front part of the foot is difficult and patients tend to drag the foot on the ground while walking. In such cases, a brace worn over the shoe and lower leg, called an ankle-foot orthosis, might help. These are custom made for each individual and can prevent injuries that might arise because of foot drop.

If symptoms are severe and walking is impaired, using a wheelchair can help with mobility. It is important to ensure that the wheelchair is comfortable and can be easily maneuvered. Having a single footplate helps in resting the legs and  facilitates easy passage through doorways.

Regular monitoring of complications

Some forms of TMD in which both copies of the TTN gene are mutated might result in more severe symptoms, such as cardiac problems. Therefore, it is important to regularly monitor any signs of heart complications such as arrhythmia (abnormal heart rate) and seek the advice of a cardiologist.

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