{"id":27132,"date":"2024-05-26T13:34:03","date_gmt":"2024-05-26T11:34:03","guid":{"rendered":"https:\/\/www.krebs-praedisposition.de\/?post_type=kompendium&p=27132"},"modified":"2025-08-26T11:51:17","modified_gmt":"2025-08-26T09:51:17","slug":"mutyh-associated-polyposis","status":"publish","type":"kompendium","link":"https:\/\/www.krebs-praedisposition.de\/en\/kompendium\/mutyh-associated-polyposis\/","title":{"rendered":"MUTYH-Associated Polyposis"},"content":{"rendered":"

MUTYH-Associated Polyposis \u2013\u00a0Definition<\/h2><\/div>
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MUTYH-associated polyposis (MAP, OMIM #608456) is a genetic disease caused by a biallelic pathogenic variant in the MUTYH<\/em> gene that predisposes to colorectal carcinoma. Carcinomas and commonly occurring adenomatous colon polyps (between 10 and a few hundred) generally do not appear until adulthood. In addition, there is also an increased risk of developing duodenal polyps and a duodenal carcinoma. Extraintestinal manifestations are possible as well.<\/p>\n<\/div>

Synonyms:<\/p>\n<\/div><\/div><\/div>

Familial adenomatous polyposis 2 (FAP2)<\/p>\n

Colorectal adenomatous polyposis, autosomal recessive<\/p>\n

Multiple colorectal adenomas, autosomal recessive<\/p>\n<\/div><\/div><\/div><\/div>

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Gene:<\/p>\n<\/div><\/div><\/div>

MUTYH<\/i><\/p>\n<\/div><\/div><\/div><\/div>

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Gen\u00ade product:<\/p>\n<\/div><\/div><\/div>

MUTYH<\/p>\n<\/div><\/div><\/div><\/div>

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Function:<\/p>\n<\/div><\/div><\/div>

Adenine-DNA glycosylase, a DNA repair enzyme (base excision repair)
\nA defect leads to an accumulation of G:C>T:A transversions, resulting in a stop codon in the mRNA following replication and, thus, to a protein malfunction.<\/p>\n<\/div><\/div><\/div><\/div>

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Pattern of inheritance:<\/p>\n<\/div><\/div><\/div>

Autosomal recessive<\/p>\n<\/div><\/div><\/div><\/div>

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Prevalence:<\/p>\n<\/div><\/div><\/div>

1-2% of the population in Northern Europe is heterozygous for a pathogenic MUTYH variant.
\nThe prevalence of biallelic pathogenic MUTYH variants is around 1:20,000-1:40,000.<\/p>\n<\/div><\/div><\/div><\/div>

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Genotype-phenotype correlation:<\/p>\n<\/div><\/div><\/div>

Patients with a homozygous c.536A>G pathogenic variant have a greater risk of a severe disease progression and early onset (around 8 years earlier) of the disease than patients with a homozygous mc.1187G>A pathogenic variant.<\/p>\n<\/div><\/div><\/div><\/div>

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Penetrance:<\/p>\n<\/div><\/div><\/div>

High for colorectal carcinoma, but incomplete (lifetime risk 43-100%)
\nUnknown for colorectal polyps, but probably incomplete (around one third of patients with colorectal carcinoma do not present with any polyps)<\/p>\n<\/div><\/div><\/div><\/div><\/div><\/div>

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Overview of the Chapters on This Page:<\/h4><\/div><\/div><\/div>