Ataxia telangiectasia (A-T) (also referred to as Louis–Bar syndrome ) is a rare, neurodegenerative, autosomal recessive disease causing severe disability. Ataxia refers to poor coordination and telangiectasia to small dilated blood vessels, both of which are hallmarks of the disease. A-T affects many parts of the body: * It impairs certain areas of the brain including the cerebellum, causing difficulty with movement and coordination. * It weakens the immune system, causing a predisposition to infection. * It prevents repair of broken DNA, increasing the risk of cancer.