Contributor: Gordon K. Klintworth
Ataxia telangiectasia (Louis-Bar syndrome) is an autosomal recessive inherited syndrome with a diverse phenotype that includes ataxia and the presence of telangiectatic blood vessels with telangiectasia. 0.5%-1% of the population is suspected to be carriers of the mutant gene. In most cases the mutated ATM gene produces a truncated protein. Manifestations of the condition include cerebellar ataxia, oculocutaneous telangiectasia, hypersensitivity to radiation, increased susceptibility to cancer, an immunodeficiency state and chromosomal instability. There is an increased susceptibility to breast carcinoma  [carcinoma - breast] even in heterozygous carriers.The serum alpha-fetoprotein is elevated.