ATM mutation is seen in

(A) Ataxia telangiectasia # Ataxia telangiectasia mutated (ATM) is a serine/threonine protein kinase that is recruited and activated by DNA double-strand breaks.> ATM phosphorylates several key proteins that initiate activation of the DNA damage checkpoint, leading to cell cycle arrest, DNA repair or apoptosis.> Several of these targets, including p53, CHK2 and H2AX are tumor suppressors.> Ataxia telangiectasia (autosomal recessive): 11 q22-23; ATM gene for regulation of cell cycle; mitogenic signal transduction and meiotic recombination Ataxia-telangiectasia - caused by mutations in the ATM gene Breast cancer - associated with the ATM gene Other cancers - increased risk from variations of the ATM gene Cancers of the stomach, bladder, pancreas, lung, and ovaries occur more frequently in ATM mutation carriers than in people who do not carry these mutations.