Lower Incidence of Colorectal Cancer and Later Age of Disease Onset in 27 Families With Pathogenic <i>MSH6</i> Germline Mutations Compared With Families With <i>MLH1</i> or <i>MSH2</i> Mutations: The German Hereditary Nonpolyposis Colorectal Cancer Consortium

Later age of disease onset and lower incidence of colorectal cancer may contribute to a lower proportion of identified MSH6 mutations in families suspected of HNPCC. However, in approximately half of these families, at least one patient developed colorectal or endometrial cancer in the fourth decade of life. Therefore, a surveillance program as stringent as that for families with MLH1 or MSH2 mutations is recommended.