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Congratulations, You Don’t Have a BRCA Mutation! But Wait … Could You Have Lynch Syndrome?

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Last Update: March 6, 2019

Errors in genetic testing are unfortunately commonplace. One of the most common genetic testing errors involves recognizing that genetic testing is appropriate but ordering the wrong test.  For instance, people who have a personal and/or family history suggestive of Lynch syndrome may mistakenly have only the BRCA1 and BRCA2 genes tested.

In one such case, two sisters diagnosed with early-onset ovarian cancer tested BRCA negative and were told “lightning struck twice”. It wasn’t lightning, it was Lynch syndrome. A detailed family history revealed that the sisters had multiple family members with cancers of the uterus, gastrointestinal, and urinary tracts. Important message here: ideally, a certified genetic counselor should assess your case before you have genetic testing to ensure that the correct tests are ordered and after your testing so that your results are interpreted and applied accurately.

Lynch syndrome is a hereditary cancer syndrome that can be caused by mutations in one of five different genes. People with Lynch syndrome are at increased risk to develop colorectal, uterine, and ovarian cancers, as well as other cancers of the gastrointestinal and urinary tracts. They are also more likely to be diagnosed with cancer at younger ages (often before age 50) than are other people in the general population, and their risk to develop more than one of these cancers is increased. Skin findings such as sebaceous adenomas and carcinomas can also occur.

Lynch syndrome affects both men and women. If someone has this condition, there is a 50% chance to pass it to each child. Luckily, genetic counseling and testing are available. When we know that a person has Lynch syndrome, he/she can be offered early and more aggressive surveillance, surgeries, and potentially medications that can detect cancer earlier and/or reduce the risk of developing cancer.

If any of the following factors have been seen in your personal and/or family history, you may wish to explore your options for genetic counseling and testing for the genes involved in Lynch syndrome:

  • Early-onset colon or uterine cancer (under <50 years)
  • Clusters of colon, uterine, ovarian, biliary or urinary tract cancers on the same side of the family
  • One family member who has developed multiple, primary (new) colon, uterine, ovarian or urinary tract cancers
  • Sebaceous carcinomas/adenomas, especially in the context of a personal or family history of any of the above cancers
  • Any Lynch syndrome-related tumor (most likely, colorectal or uterine) tumor with abnormal MSI or IHC testing.

Photo by Matthias Ripp, via Flickr