Ataxia telangiectasia

Ataxia telangiectasia (A-T) is rare condition that affects the nervous system, the immune system, and many other parts of the body. Signs and symptoms of the condition usually begin in early childhood, often before age 5. The condition is typically characterized by cerebellar ataxia (uncoordinated muscle movements), oculomotor apraxia, telangiectasias, choreoathetosis (uncontrollable movements of the limbs), a weakened immune system with frequent infections, and an increased risk of cancers such as leukemia and lymphoma.^[1][2] A-T is caused by changes (mutations) in the ATM gene and is inherited in an autosomal recessive manner.^[3] Treatment is supportive and based on the signs and symptoms present in each person.^[2]

Ataxia-telangiectasia affects the nervous system, immune system, and other body systems. This disorder is characterized by progressive difficulty with coordinating movements (ataxia) beginning in early childhood, usually before age 5. Affected children typically develop difficulty walking, problems with balance and hand coordination, involuntary jerking movements (chorea), muscle twitches (myoclonus), and disturbances in nerve function (neuropathy). The movement problems typically cause people to require wheelchair assistance by adolescence. People with this disorder also have slurred speech and trouble moving their eyes to look side-to-side (oculomotor apraxia). Small clusters of enlarged blood vessels called telangiectases, which occur in the eyes and on the surface of the skin, are also characteristic of this condition.^[3]

Affected individuals tend to have high amounts of a protein called alpha-fetoprotein (AFP) in their blood. The level of this protein is usually increased in the bloodstream of pregnant women. The effect of abnormally high levels of AFP in people with ataxia-telangiectasia is unknown.^[3]

People with ataxia-telangiectasia often have a weakened immune system, and many develop chronic lung infections. They are also at an increased risk of developing cancer, particularly leukemia and lymphoma. Affected individuals are very sensitive to the effects of radiation exposure, including medical x-rays. Although people with ataxia-telangiectasia usually live into adulthood, their life expectancy is reduced.^[3]