Specific ‘Mendelian’ CRC syndromes include familial adenomatous polyposis (FAP), with gene mutation of the adenomatous polyposis coli (APC) gene, LS genes (MSH2, MLH1, MSH6, PMS2), Peutz–Jeghers syndrome (LKB1/STK11), juvenile polyposis (SMAD4, BMPR1A), MUTYH-associated polyposis, and hereditary mixed polyposis (GREM1). This evidence concerns the gene MLH1 and colorectal carcinoma.