Walsh & Hoyt: Ataxia Telangiectasia (Ch. 47)

Ataxia telangiectasia (AT) belongs to a group of inherited conditions, known as the genomic instability syndromes, that are characterized by vulnerability to genetic damage. It is an autosomal-recessive disorder caused by mutations in the gene encoding ATM, a phosphatidylinositol kinase that is central in orchestrating the cellular response to damaged DNA. Although the clinical features normally become manifest in childhood, cases with a more benign course can be identified in adults (239). It is now recognized that some of these patients carry a genetic defect in another gene involved in genomic maintenance, Mre11, and their condition is designated as AT-like disorder (ATLD) (240).