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MUTYH gene

Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

MUTYH gene

The MUTYH gene provides instructions for an enzyme that repairs DNA by correcting errors that occur during cell division.

Normal Function

The MUTYH gene provides instructions for making an enzyme called adenine DNA glycosylase. This enzyme is a critical component of the base excision repair process. During DNA replication, chemical bases (adenine, thymine, guanine, and cytosine) must pair correctly. Occasionally, guanine is altered by oxidation, causing it to pair incorrectly with adenine. Adenine DNA glycosylase identifies and removes the mismatched adenine, allowing the error to be fixed.

Health Conditions Related to Genetic Changes

MUTYH-associated polyposis

Variants (mutations) in the MUTYH gene cause MUTYH-associated polyposis (MAP). This inherited disorder is characterized by a significantly increased risk of colorectal cancer and other types of cancer.

In individuals with MAP, both copies of the MUTYH gene are altered, leading to the production of a nonfunctional or poorly functioning adenine DNA glycosylase enzyme. When this repair process is impaired, DNA errors—specifically transversions where adenine pairs with oxidized guanine—accumulate as cells divide. If these errors occur in genes that regulate cell growth, it can lead to uncontrollable cell growth and cancer.

Other Names for This Gene

  • hMYH
  • mutY homolog
  • MUTYH_HUMAN
  • MYH

Frequently Asked Questions

Early signs of MAP often include the sudden appearance of multiple colorectal polyps, especially if you are under 50 years old. You may also notice changes in bowel habits, such as frequent diarrhea or constipation, rectal bleeding, or unexplained anemia. If you have a family history of colorectal cancer or polyps, these symptoms warrant prompt evaluation with a colonoscopy.
Having a single (heterozygous) mutation generally confers a modestly increased risk for colorectal cancer, similar to that of a first-degree relative of a MAP patient. Biallelic (two) mutations cause classic MAP with a high polyp burden and a much greater cancer risk. Genetic counseling can help interpret your specific mutation status and guide surveillance.===
Yes. Maintaining a high-fiber, low-fat diet, regular physical activity, avoiding smoking, limiting alcohol, and managing body weight can help reduce overall colorectal cancer risk. Some evidence suggests that aspirin or other NSAIDs may lower polyp formation in MAP patients, but this should be discussed with your gastroenterologist.
For individuals with biallelic MUTYH mutations (two copies altered), colonoscopy is recommended every 1 to 2 years starting at age 25 or 8–10 years before the earliest colorectal cancer case in the family, whichever comes first. If only one mutation is present, screening is typically every 3 to 5 years, but this can be adjusted based on family history and polyp burden.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.