ABSTRACT
Ataxia telangiectasia (AT) is a multisystem autosomal recessive disorder by mutations in a single gen e , A TM. A large number of mutations in this gene have been identified so far. In most cases of AT patients, null ATM mutations lead to truncated or greatly destabilized protein. AT variants, who show milder manifestations of the clinical or cellular characteristics of the disease, exhibit reduced but detectable level of the ATM protein; these patients show the expected mild phenotype. The large size of the ATM gene and the diversity and broad distribution of mutations in AT patients lim it the efficient screening of mutations as a diagnostic tool.
