Skip to main content

Lynch Syndrome (LS)

Lynch syndrome (LS) is an inherited condition that is associated with an increased risk of the following cancers:

  • Colorectal
  • Endometrial
  • Ovarian
  • Gastric
  • Small bowel
  • A number of other cancers may have an increased risk in Lynch syndrome: Hepatobiliary tract, urinary tract, brain, sebaceous neoplasms, prostate, pancreas, and breast

Lynch syndrome was previously known as hereditary nonpolyposis colorectal cancer (HNPCC). Lynch syndrome affects both men AND women. It is caused by mutations or changes in one of five different genes. People with a first degree relative (mother, father, sibling, child) with a mutation in one of these genes has a 50% chance of also having the mutation. One of the objectives of Healthy People 2020 is to increase the proportion of newly-diagnosed colorectal cancer patients who receive genetic testing to identify LS. The objective is based on national evidence-based recommendations that LS screening be considered for these individuals. Early identification of LS may help reduce the impact of cancer and save the lives of at-risk family members.

Should I be tested for Lynch Syndrome?

People with a significant personal or family history of the above cancers should be referred for genetic counseling to discuss their risk. But what is a significant personal or family history? This includes people who:

1. Have a family member with a known gene change (mutation) in a LS gene

2. Have a personal history of cancer:

  • Have a personal history of colorectal or endometrial cancer before the age of 50
  • Have a personal history of colorectal or endometrial cancer and a personal history of another LS-related cancer
  • Have a personal history of colorectal or endometrial cancer and one relative (mother, father, aunt, uncle, child, sibling) with a LS-related cancer
  • Have a personal history of colorectal or endometrial cancer that have abnormal tumor testing (See tumor testing below)

3. Has not had cancer, but has a family member (mother, father, sibling, child) who:

  • Has been diagnosed with colorectal or endometrial cancer before the age of 50
  • Has been diagnosed with colorectal or endometrial cancer at any age AND another LS-related cancer

4. Has not had cancer, but has two or more family members (mother, father, sibling, aunt, uncle, child) who have been diagnosed with a LS-related cancer

Family History and Lynch Syndrome

Family history plays a key role in finding people at risk for Lynch syndrome. Your doctor or genetic counselor can use family history to help decide if you should have genetic testing for LS. There are many resources that have been made to assess your risk and help you take action based on your family health history. If LS is suspected based on personal and family history, the next step is to talk to your health care provider and look for genetic counseling from a qualified professional. More information:

Cancer Genetic Counseling and Testing for Lynch Syndrome

Cancer genetic counselors are professionals who have specialized education in genetics and counseling to provide information on your risk of developing cancer. Genetic counselors can work with you and your doctor to understand complex genetic information and help you make informed decisions. They can also provide emotional support as you make these decisions.

Genetic counseling is a process that helps identify a person’s risk of LS. Genetic counseling does not always lead to genetic testing and a patient can always choose not to undergo genetic testing. A genetic counseling session can include:

  • Gathering of individual and family health history
  • Assessment of cancer risk
  • Genetic counseling before and after any recommended tests
  • Informed consent for all recommended procedures
  • Guidance on cancer prevention measures, in case of positive test results
  • Possible screening of family members who may carry the same mutation

Genetic counseling and genetic testing can help determine if a person’s cancer is inherited and whether family members have a higher chance of developing the same cancer. Having this knowledge is the first step in cancer prevention and intervention. It can protect the health and save the lives or relatives who are at-risk.

For more information about cancer genetic counseling please see the MCGA Position Paper: Genetic Counseling and Testing for Hereditary Cancer Predisposition Syndromes (pdf). To find a genetic counselor near you, please see: Genetic Counselors in Michigan


Contact Us

If you have questions, call the MDHHS Genetic Information Line at 1-866-852-1247 or email

Genomics and Genetic Disorders Section 
Lifecourse Epidemiology and Genomics Division 
P.O. Box 30195
333 S. Grand Avenue
Lansing, Michigan 48909-30195



Funding for this program was made possible (in part) by the Centers for Disease Control and Prevention. The views expressed in written materials, publications, or webpages do not necessarily reflect the official policies of the U.S. Department of Health and Human Services, nor does the mention of trade names, commercial practices, or organizations imply endorsement by the U.S. Government.

Last updated: 6/23/2022