Lynch syndrome, previously called hereditary nonpolyposis colorectal cancer, is one of the most common hereditary cancer syndromes. A person is diagnosed with Lynch syndrome if they inherit a mutation in the MLH1, MSH2, MSH6, PMS2, or EPCAM genes.

What cancers are associated with Lynch syndrome?

A person who has Lynch syndrome has an increased risk of colon cancer or rectal cancer, which usually develops from a polyp called an adenoma. Lynch syndrome is also associated with an increased risk of cancers of the stomach and small intestine, certain urinary tract cancers, and others.

Women with Lynch syndrome have an elevated risk of developing uterine (endometrial) cancer or ovarian cancer.

The exact risks for these types of cancer may differ depending on which gene is affected, family history, and possibly environmental risk factors.

It is important to understand that having Lynch syndrome does not mean that a person will develop cancer. It only means that they have an increased risk of developing certain types of cancers. The age at diagnosis and type of cancer can vary among people with Lynch syndrome, even within the same family.

Distinct variations of Lynch syndrome include other features:

• Muir-Torre syndrome is associated with the standard Lynch syndrome–related cancers and a type of skin cancer called sebaceous gland lesions.
• Turcot syndrome is associated with colorectal cancer or colorectal polyps (adenomas) and a type of brain tumor called glioblastoma.
• Constitutional mismatch repair deficiency (CMMR-D) syndrome has been associated with childhood cancers, including leukemia, brain cancer, and colorectal cancer. People with CMMR-D often have multiple large brown spots on the skin (known as café au lait spots). People with CMMR-D have mutations in both copies of one of the Lynch syndrome genes (one from each parent), while people with typical Lynch syndrome carry only one mutation (from just one parent).

What can a person with Lynch syndrome do to manage their cancer risk?

We recommend that people with Lynch syndrome pursue specialized cancer surveillance examinations. This includes colonoscopy, upper endoscopy, and urine testing.

People with Lynch syndrome may consider certain risk-reducing procedures, which include the removal of the uterus and ovaries.

Recommendations on the best way for you to manage your individual cancer risk should be discussed with a genetic counselor or doctor who is experienced in the care of people with Lynch syndrome.

How is Lynch syndrome passed down through a family?

Lynch syndrome can be passed from a mother or father to a son or daughter. People with a first-degree relative (a parent, sibling, or child) with Lynch syndrome have a 50% chance of having inherited it.