Ataxia-telangiectasia (A-T) is an autosomal recessive neurodegenerative genetic disorder characterized by progressive ataxia due to cerebellar degeneration, oculocutaneous telangiectasia, immunodeficiency with recurrent sinopulmonary infections, significant sensitivity to ionizing radiation, and increased risk of cancers, especially lymphoma and leukemia. Incidence is estimated as 1 in 40,000 births, although this may be an underestimate due to early deaths prior to diagnosis. There are between 500 and 600 cases of A-T in the United States. Occurrence has shown no bias on racial, gender, geographic, or other lines. It is estimated that 1% of the general population is a carrier for one of the mutated A-T genes, and carrier status itself is associated with lower than normal tolerance for radiation and an increased risk of cancer for both genders. For females, it is estimated that A-T carriers comprise approximately 6-9% of all breast cancer cases, and carrier status is associated with a three- to five-times greater risk of developing breast cancer (Lavin, 1998). Thus, this disorder carries health implications for both homozygote patients as well as heterozygote parent carriers. Well siblings have a two-thirds chance for being carriers.
A degenerative brain disease of children, marked by cellular and humoral immunodeficiency, progressive cerebellar degeneration, telangiectasis of the bulbar conjunctiva, and increased risk of malignancy. It is transmitted as an autosomal recessive trait. Death usually occurs in adolescence or early adulthood. Parents should be informed that subsequent children have a 25% risk of having this condition.
Louis-Bar syndrome, also known as ataxia-telangiectasia, is a rare hereditary neurodegenerative disorder that can result in profound disability. The term “ataxia” pertains to impaired coordination, while “telangiectasia” refers to the presence of small dilated blood vessels.