MUTYH associated polyposis

Topic Completed: 2 February 2021

Minor changes: 2 February 2021

Copyright: 2002-2021,, Inc.

PubMed Search: MUTYH associated polyposis [title]

Raul S. Gonzalez, M.D.
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Cite this page: Gonzalez RS. MUTYH associated polyposis. website. Accessed October 28th, 2021.
Definition / general
  • Autosomal recessive polyposis syndrome characterized by development of numerous colon adenomas but usually fewer than in classic familial adenomatous polyposis
Essential features
  • Attenuated polyposis syndrome with biallelic MUTYH mutations and no FAP mutation
  • Increased risk for colorectal carcinoma
  • Outdated terms include:
    • MYH associated polyposis
    • Familial adenomatous polyposis 2
    • Autosomal recessive adenomatous polyposis
Clinical features
  • Mean age of diagnosis is about 50 years
  • Patients often have between 10 and 100 polyps (Int J Cancer 2004;109:680)
  • Biallelic mutations confer a 50 fold risk of colorectal carcinoma and monoallelic mutation a 3 fold risk (Cancer Epidemiol Biomarkers Prev 2006;15:312)
  • Patients can also develop ovarian, bladder and breast carcinoma, as well as sebaceous gland tumors
  • Molecular testing to confirm biallelic MUTYH mutations
Case reports
Microscopic (histologic) description
  • Patients most commonly develop colonic tubular adenomas that resemble sporadic adenomas
  • Sessile serrated polyps can also occur
Microscopic (histologic) images

Contributed by Raul S. Gonzalez, M.D.

Adenoma associated with MUTYH mutation

Molecular / cytogenetics description
  • MUTYH is located at 1p34 and repairs oxidative DNA damage that otherwise can lead to carcinoma (Mod Pathol 2013;26:1371)
  • Most common mutations are Y165C and G382D
Differential diagnosis
Board review style question #1
How does MUTYH associated polyposis differ from familial adenomatous polyposis?

  1. It is autosomal recessive
  2. Molecular testing cannot confirm the diagnosis
  3. Patients never develop upper gastrointestinal tract adenomas
  4. The polyps are all serrated
Board review style answer #1
A. It is autosomal recessive

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