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Exploring POLE Genes! Day 7 Hereditary Cancer Awareness

Courtesy of ICARE

Polymerase proof-reading associated polyposis (PPAP) is a rare hereditary polyposis condition. It is caused by mutations in an important

region of the POLE and POLD1 genes called the exonuclease domain. Individuals often develop at least a dozen polyps, but this number can vary, ranging from zero or one to 100 polyps. Adenomas are the predominant polyp type seen with PPAP, and the lifetime risk for colon cancer is estimated to be at least 50%.

The mutations in the POLE and POLD1 genes that are associated with PPAP are inherited in a dominant manner. The condition is rare and its exact prevalence is unknown, with its contribution to hereditary colon cancer being less than 1%. Although rare, it is extremely important to identify individuals and families with PPAP as the risk for other cancers also appears to be increased.

These risks include uterine cancer, brain cancer, ovarian cancer, duodenal cancer, as well as possibly others. Current guidelines recommend that individuals with mutations in the POLD1 and POLE genes start colonoscopy screening by the age of 25-30.

Although no formal screening recommendations currently exist for other cancers, such as uterine, ovarian, or duodenal, proposed guidelines are emerging and attention should be paid to family histories that may warrant additional screening.

Learn more about PPAP by browsing the link below:

To find an inherited GI Cancer Genetics Clinic near you, check out the “Find a Clinic” page on the CGA-IGC website:

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