In humans, MUTYH-associated polyposis(MAP) islinked to biallelic inherited germline mutations in the MUTYH gene and leads to increased risk of developing colorectal carcinomasand adenomas.16−19 MAP was first discovered in a family that presented with multipleadenomatous polyps in the colon, which is most commonly due to germlinemutations in the APC gene; however, inherited APC mutations were lacking in this family.20 DNA from adenomas of these individuals exhibited unusuallyhigh levels of G:C to T:A mutations, suggesting defective repair ofOG. Here, MUTYH is linked to polyposis.