Pathogenic variants (disease-causing) in both copies of the MUTYH gene cause MUTYH-associated polyposis (MAP), a recessive condition in which people typically develop multiple colorectal polyps (often 10–100 by age 50) and have a high lifetime risk of colorectal cancer. Reported colorectal cancer risks in biallelic MUTYH carriers range widely across studies. MAP can also be associated with stomach and small-bowel polyps and may increase risk of other gastrointestinal cancers. Management of MUTYH–related tumor risk includes regular surveillance tailored to guidelines to detect tumors early. MUTYH variants are not known to be more common in the Ashkenazi Jewish population.
As noted above, MAP exhibits autosomal recessive inheritance. This means that both parents must be carriers of an MUTYH pathogenic variant to have a 25% chance to have a child with the condition; a carrier means that an individual has a single MUTYH pathogenic variant. Carriers, to the best of our knowledge, do not have an increased of cancer or polyps. If an individual has MAP, the chance their children could have it depends on the genetic make-up of the other parent.
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Written December 2025
