It is characterized by a dominantly inherited predisposition to early onset colorectal carcinoma and certain extra colonic tumours, caused by germline mutations in DNA mismatch repair (MMR) genes, most commonly in MLH1 and MSH2[1]–[3].The genetic diagnosis of this inherited predisposition offers an opportunity for intensive targeted clinical surveillance of healthy carriers, which has been proven to reduce significantly cancer morbidity and mortality [4]. Here, MSH2 is linked to colorectal carcinoma.