The ATM gene (mutated in the disease ataxia telangiectasia) activates the p53 tumor suppressor protein in response to DNA damage, explaining the higher incidence of cancer in AT patients.

and four (ataxia-telangiectasia, ataxia-telangiectasia-like disorder, Nijmegen breakage syndrome and Alzheimer's disease) exhibit defects in genes involved in repairing double-strand breaks.