Ataxia-Telangiectasia (AT) is an inherited disorder that affects the nervous system, immune system, and other systems in the body. People with AT develop progressive difficulty with coordinating movements in early childhood. Other movement and neurological problems may develop, and the affected children may be wheelchair bound by adolescence. One of the characteristics of this condition is called telangiectases, which are small clusters of enlarged blood vessels in the eyes or on the surface of the skin. Individuals with AT often have a weak immune system and a high risk to develop cancers. The life expectancy of people with AT may be shortened, but most can live into adulthood. Intellectual disability or learning problems are not associated with AT. AT is caused by pathogenic variants in the ATM gene.