a) 56 Lynch syndrome (MSH2, MLH1, MSH6, PMS2)b) 10 familial adenomatous polyposis (APC, MUTYH)c) 13 mutations in other cancer-associated genes (MUTYH, SMAD4, BRCA1, TP53, CHEK2). The gene discussed is CHEK2; the disease is Familial adenomatous polyposis.