Genetic Testing for Lynch Syndrome

Genetic testing is available for Lynch syndrome. However, most colorectal cancer is not caused by inherited mutations, so Lynch syndrome testing will not benefit most people with a family health history of colorectal cancer who have not had cancer themselves. Genetic testing will not identify the cause for some hereditary colorectal cancers, because the genes affected in these cancers are not yet known.

Usually, genetic testing will be recommended if
  • Your tumor screening results (IHC or MSI) are abnormal
  • You have had colorectal cancer
  • You had uterine (endometrial cancer) before age 50
  • You have had multiple primary cancer diagnoses
  • Several family members have had cancers related to Lynch syndrome
  • You have a family member with Lynch syndrome

Genetic testing looks for inherited Lynch syndrome mutations. Your doctor may recommend a multi-gene panel, which looks for mutations in several genes at the same time, including the genes associated with Lynch syndrome.

The genetic counselor can help to determine the best testing strategy for you and your family. When possible, testing should start with someone in the family who has had cancer. However, if none of your family members who have had cancer are available for testing, genetic testing can start with an unaffected person.

Genetic Testing Results

Interpretation of genetic testing results may vary, depending on whether you have had colorectal cancer in the past or not.

Page last reviewed: March 4, 2019