JAMA : the journal of the American Medical Association
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Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is caused by mutations in the mismatch repair genes and confers an extraordinarily high risk of colorectal, endometrial, and other cancers. However, while carriers of these mutations should be identified, counseled, and offered clinical surveillance, at present the mutations are not tested for in mutation analyses. ⋯ The postulated high frequency and continent-wide geographic distribution of a cancer-predisposing founder mutation of the MSH2 gene in a large, outbred (as opposed to genetically isolated) population, and the ease with which the mutation can be detected, suggest that the routine testing of individuals at risk for HNPCC in the United States should include an assay for this mutation until more is learned about its occurrence.