May also be called: A-T, Ataxia-Telangiectasia, Louis-Bar Syndrome, LBS

Ataxia telangiectasia (ay-TAK-see-uh teh-lan-jek-TAY-zhee-uh) is a rare genetic disorder that causes immune deficiencies and degeneration of the part of the brain that controls movement and speech.

More to Know

Ataxia telangiectasia (A-T) happens when a child inherits two mutated copies of a gene that helps control cell division and DNA repair. A-T is an autosomal recessive disorder, which means that two healthy parents who each have one mutated copy of the gene have a 1 in 4 chance of having a child affected by A-T.

A-T is usually noticed in the second year of life as a child develops problems with balance and slurred speech caused by ataxia (lack of muscle control). The ataxia occurs because the cerebellum, the part of the brain that controls muscle movement, becomes weaker over time. Eventually, the lack of muscle control becomes severe enough for the child to require a wheelchair, usually by early adolescence.

Other symptoms of A-T include abnormal eye movements and tiny, red, spiderlike veins in the corners of the eyes or on the ears and cheeks when exposed to sunlight. These veins, known as telangiectasias, are harmless. About 70% of children with A-T also have immune system problems that make them more susceptible to lung disease. These children often have chronic upper respiratory infections, lung infections, and pneumonia. They're also more likely to develop certain cancers, such as leukemia and lymphoma.

Treatment for A-T is focused on treating symptoms and related conditions and may involve medications to treat infections and bolster the child’s immune system, as well as physical therapy and occupational therapy to help maintain flexibility and address slurring and other speech problems.

Keep in Mind

Currently, there is no cure for A-T and no way to stop its progression, but proper treatment can help kids manage symptoms and achieve their best possible quality of life. The expected life span of a child with A-T depends upon the severity of the condition.

All A to Z dictionary entries are regularly reviewed by KidsHealth medical experts.