The final sample comprised 2023 carriers; of whom 694 (34.3%) were probands; 1141 (56.4%) were females, 1492 (73.8%) were recruited from familial cancer clinics; 737 carried a mutation in MLH1, 928 in MSH2, 230 in MSH6, 106 in PMS2, and 22 in EPCAM. Participants were from 773 families, of which 431 had one affected relative, 148 had more than one affected relative, and 194 had no affected relative. The gene discussed is MSH2; the disease is cancer.