MUTYH- Associated Polyposis

Lynch syndrome and familial adenomatous polyposis (FAP) have long been identifi ed as hereditary predisposition syndromes to colorectal cancer (CRC), most easily recognized on the basis of their autosomal dominant inheritance, young age of onset of CRC and other associated malignancies, and, in the case of FAP, the presence of adenomatous polyposis. However, in 2002 the fi rst report of a novel hereditary predisposition to CRC describing a family with three siblings affected with CRC and polyposis who were negative for germline APC mutations was published [ 1 ]. These siblings were identifi ed to carry biallelic germline mutations in the MUTYH gene, also known as MYH . This autosomal recessive predisposition to CRC has been termed MYH or MUTYHassociated polyposis (MAP, OMIM #608456) and has been recognized as a rare, but important, cause of hereditary CRC, representing less than 1 % of CRC cases [ 2 ], and posing challenges in diagnosis, genetic counseling, and surveillance.