ATM (DNA-damage-response gene)

ATM (short for ataxia-telangiectasia mutated) is a gene that makes a protein kinase. That kinase is the master alarm for one of the worst kinds of DNA damage: a double-strand break. When it fires, it tags hundreds of other proteins (including H2AX, CHK2, p53, and BRCA1) to halt the cell cycle, repair the DNA, or trigger cell death. Inherit two broken copies and you get ataxia-telangiectasia. It is a recessive disease marked by failing balance (cerebellar degeneration), a weak immune system, extreme radiation sensitivity, and a cancer risk above 30%. Carry just one faulty copy (about 1% of people) and your cancer risk is in between, especially for breast and colorectal cancer. Recent data hint at somewhat higher heart-disease risk too. That puts ATM among the cancer-risk genes worth acting on. In aging biology, weak ATM shows how a broken DNA-damage response speeds up hallmarks like genome instability and inflammation.

Last reviewed: June 22, 2026

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