Lynch syndrome

Lynch syndrome is an inherited bowel cancer syndrome that accounts for approximately 2–5% of all bowel cancers.

For more detailed information about Lynch syndrome please download the Lynch Syndrome Information Guide (PDF).

What is Lynch syndrome?

Lynch syndrome was previously known as HNPCC (hereditary non-polyposis colorectal cancer).

Not everyone with Lynch syndrome will develop bowel cancer. However, a person who inherits a Lynch syndrome mutation has increased risk—generally around 30–50% unless preventative measures are taken. Developing bowel cancer at a young age is not uncommon.

Lynch syndrome is caused by a change in a gene that normally functions to protect a person from getting cancer. If you have a parent or sibling with Lynch syndrome, you are potentially at risk of having Lynch syndrome.

If you have been diagnosed with Lynch syndrome, your children are at risk. When a parent carries a change known as a mutation each child will have a 50:50 chance of inheriting the gene mutation.

Not all people with Lynch syndrome have a family history of Lynch syndrome. However, some people may be the first in their family to get Lynch syndrome. If you are the first one in your family to get Lynch syndrome, each of your children still have the same 50:50 chance of inheriting the mutation.

In men and women with Lynch syndrome, cancers can also occur in the kidney, ureter (the tube from the kidney to the bladder) and in parts of the gut such as the small bowel (intestine), stomach or pancreas.

Women also have an increased risk of cancer of the inner lining of the uterus (endometrium) and the ovaries.


Regular check-ups

If you are a member of a family affected by Lynch syndrome you should have regular bowel screening, often beginning in your early to mid–20s.

For this procedure, called a colonoscopy, a specialist uses a long flexible tube to examine the lining of your colon (large intestine) for any polyps or signs of cancer.

Other check-ups, surgery, or treatment may be advised depending on your personal history and/or family history and should be discussed with your doctor.

Please visit the eviQ website for the latest Risk Management guidelines for Lynch Syndrome

There are also fact sheets for people and families with a Lynch syndrome where genetic testing has identified the specific faulty gene, including:

Genetic testing

So far, four different genes have been found to be associated with Lynch syndrome: MLH1, MSH2, MSH6 and PMS2. A mutation in one of these genes can cause Lynch syndrome. The EpCAM gene is sometimes also associated with Lynch Syndrome.

Genetic testing involves a blood test. The initial genetic testing in a family (called a mutation search) must be done in someone in the family who has developed a Lynch syndrome cancer. If a mutation is identified in that person, other relatives at risk of carrying the mutation can then be tested.

Sometimes a mutation cannot be found in the family. In this case, Lynch syndrome may be due to other gene changes that research has not yet identified. If the family mutation is not found, genetic testing is not able to be offered to other family members.

If a family mutation is found, the rest of the family can be offered predictive testing. This means testing to see if you have inherited Lynch syndrome, even though you may not have any signs or symptoms yet.

For further information speak with a Genetic Counsellor.

What if I suspect I have Lynch syndrome?

Speak to your doctor, a Genetic Counsellor or call the Hereditary Cancer Registry on 1800 505 644.

For more information on hereditary cancer, please visit eviQ and click on the Cancer Genetics tab.