GTR Home > Conditions/Phenotypes > MYH-associated polyposis

Disease characteristics

Excerpted from the GeneReview: MUTYH-Associated Polyposis
MUTYH-associated polyposis (MAP), caused by biallelic mutations in MUTYH, is characterized by a greatly increased lifetime risk of colorectal cancer (CRC) (43% to almost 100% in the absence of timely surveillance). Although typically associated with ten to a few hundred colonic adenomatous polyps that are evident at a mean age of about 50 years, colonic cancer develops in some individuals with biallelic MUTYH mutations in the absence of polyposis. Duodenal adenomas are found in 17%-25% of individuals with MAP; the lifetime risk of duodenal cancer is about 4%. Also noted are a modestly increased risk for rather late-onset malignancies of the ovary, bladder, and skin, and some evidence for an increased risk for breast and endometrial cancer. More recently, thyroid abnormalities (multinodular goiter, single nodules, and papillary thyroid cancer) have been reported in some studies. Some affected individuals develop sebaceous gland tumors.

Associated genes

Clinical features

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  • Adenomatous colonic polyposis
  • Colon cancer
Go to complete MedGen record for MYH-associated polyposis

Clinical resources

Practice guidelines

  • ACMG, 2013
    ACMG recommendations for reporting of incidental findings in clinical exome and genome sequencing.
  • EuroGenetest, 2010
    Clinical utility gene card for: MUTYH-associated polyposis (MAP), autosomal recessive colorectal adenomatous polyposis

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