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Lynch Syndrome: The Genetic Side of Colorectal Cancer

Michigan Gov. Rick Snyder has designated March 22 Lynch Syndrome Awareness Day.

Her aunt died of colon cancer at age 72.  Her cousin died of colon cancer at age 49.  When her mother was diagnosed with colon cancer at age 70, three years after being treated for uterine cancer, Paula realized it was time to act.  She had her first colonoscopy at age 41.  While the colonoscopy was normal, her doctor recognized that the pattern of cancer in the family was concerning and suggested genetic counseling.  Genetic testing in Paula’s mother found a mutation in a gene called MSH6, confirming that their family has Lynch syndrome.

Lynch syndrome is an inherited condition caused by mutations in any one of 5 genes: MLH1, MSH2, MSH6, PMS2 and EPCAM/TACSTD1.  For people who have a mutation in one of these genes, the risk for certain cancers is increased.  Colorectal cancer is the main feature of Lynch syndrome. Other cancers that can be found in families with Lynch syndrome include:

  • uterine or endometrial
  • ovarian
  • stomach or small intestine
  • biliary tract
  • sebaceous skin tumors
  • urinary tract, such as kidney

Identifying families with Lynch syndrome allows us to intervene with screening and preventive options.  Colonoscopies every year beginning at age 20 can dramatically reduce the risk of colon cancer in people with Lynch syndrome.

When Paula learned that she carried an MSH6 gene mutation, she took steps to protect herself with more frequent colonoscopies and preventive hysterectomy, and she wishes her relatives had been able to do the same.  “If my aunt had been screened, then my cousin may have been screened earlier and more frequently.  I often wonder if that would have extended their lives,” she said.

Many families affected by Lynch syndrome remain unaware of their risk.  Clues in the family that could be related to Lynch syndrome include:

  • More than one relative with colon or uterine cancer
  • Colon or uterine cancer diagnosed before age 50
  • More than one Lynch syndrome cancer in one person, such as two colon cancers, or colon and uterine cancer in the same person

The University of Michigan Comprehensive Cancer Center’s Cancer Genetics Clinic cares for more than 120 families with Lynch syndrome.  Patients concerned about possible Lynch syndrome in their families can be seen in the clinic for risk assessment, genetic counseling, discussion of genetic testing options, and management recommendations.  Patients can also learn about participating in research that is helping us learn more about cancer risks in Lynch syndrome, and what we can do to best care for these families.

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