What is MutYH-associated polyposis (MAP)?

Updated: Jun 06, 2020
  • Author: Jaime Shalkow, MD, FACS; Chief Editor: Cameron K Tebbi, MD  more...
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Answer

The most recently described adenomatous polyposis syndrome, MutYH-associated polyposis (MAP), has an autosomal recessive herency and requires an inherited mutation from each parent for the development of the disease. MAP is caused by a biallelic mutation in the MutYH gene, located in the chromosome 1p33-34, which encodes for a DNA glycosylase responsible for base excision repair; this mutation occurs in 1-2% of the general population. [4]

The polyps found in MAP are typically small tubular or tubulovillous adenomas. In untreated patients, the risk of colorectal cancer is 80% at age 80. In contrast to FAP, the clinical presentation is usually an adult patient with 10 to thousands of polyps, resembling a less severe FAP syndrome that presents during adulthood. [5]


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