[Ataxia telangiectasia and genetic predisposition to cancer].

Ataxia telangiectasia (AT) is a genetic disorder with an autosomic recessive transmission. Occurring during childhood, it affects different organs and/or systems. Physiopathology is still unclear. The first clinical signs are evident early in childhood and evolution always leads to death. The secondary cause of mortality in 10 to 15% of the affected is the development of cancers. Genetic predisposition to cancer for homozygotes, as well as for heterozygotes, is one of the most remarkable aspects of this disease. For heterozygotes the risk of cancer is three times that of the norm. The gene responsible for the disease has been cloned. Its function may resolve some questions, and provide the link between degenerative process, cancer susceptibility and immunodeficiency evident in AT patients.