Familial cases of CCA have been reported in Lynch syndrome (MIM: 120,435) caused by mutations in the DNA mismatch repair genes which include MLH1, MSH2, MSH6, PMS1, and PMS220 and in BAP1 tumor predisposition syndrome (MIM: 614,327), where the BAP1 tumor suppressor gene is mutated21,22. The gene discussed is MSH6; the disease is Lynch syndrome.