Lynch syndrome genetic and predictive testing

Cancer is a common condition. It will affect half (50%) of the population at some point. As we get older we are more likely to develop cancer as our bodies become less effective at protecting us. 

Lynch syndrome is an inherited condition that causes an increased risk of bowel cancer. It also increases the risk of developing womb (endometrial) and ovarian cancer. 

Although less common, Lynch syndrome can also cause other cancers such as: 

  • small bowel 
  • stomach 
  • pancreas 
  • skin 
  • brain 
  • kidney 
  • bladder

People with Lynch syndrome are more likely to develop cancer at younger ages and may get cancer more than once. 

In the UK:

  • around 1 in 18 women and 1 in 15 men will develop bowel cancer
  • 1 in 50 women will develop ovarian cancer,
  • womb (endometrial) cancer affects 1 in 36 females

About 10 to 15 out of 100 (10 to 15%) cases of bowel cancer happen when someone has inherited an increased risk of developing cancer.

About 2 out of 100 (2%) of these cancers are caused by a genetic condition called Lynch syndrome.


Genes are coded messages that give instructions for how cells in the body grow and function. Genes come in pairs and we inherit one copy from each parent.

The genes related to Lynch syndrome usually protect us from cancer by controlling the growth of cells.

If someone inherits a mutation (fault) in one copy of a Lynch-related gene, they will be more likely to develop Lynch-related cancers. They are also more like to get non-cancerous growths (such as bowel polyps and skin changes).

One of a number of genes can be faulty in Lynch syndrome. The most common genes are:

  • MLH1
  • MSH2
  • MSH6
  • PMS2 

If someone has a mutation in one of their copies of a Lynch syndrome related gene, they have a 1 in 2 (50%) chance of passing on this mutation to each child they have, regardless of their gender or the child’s gender.


We can carry out tests to investigate whether Lynch syndrome runs in your family.

You can read more about further genetic testing and predictive testing for Lynch syndrome.

In some families no genetic testing is possible. For these families screening for bowel cancer can still be arranged, and we can discuss options for reducing the risk of womb and ovarian cancer.

Deciding whether to be tested

Deciding to have genetic testing is a personal decision and can be a difficult and complex process.

Not everyone will choose to have genetic testing. If you decide against it you may still be eligible to have regular bowel screening and we will discuss this with you. 

You may wish to consider these points before deciding. There are no right or wrong answers to these questions, but it is worth thinking about what your answers might be, so that when you have your result you have an idea of how you may wish to proceed.


  • Why now?
  • Will it change your immediate treatment?
  • What other challenging events are happening in your life?

Psychological impact of knowing

  • How will you feel if a Lynch syndrome related gene mutation is identified?
  • How will you share this information within the family?
  • How this test result could affect you and your future?
  • Who you plan to talk to about this test and result?
  • How this test could impact on your family, children and relationships?

Assessing your own coping strategies

  • How have you dealt with difficult situations in the past?
  • What strategies do you use to help you deal with difficult news?
  • Could this have an impact on your employment or insurance?
  • How you will adjust to your result?

Next steps

  • What might you do about your risks from Lynch syndrome if we find that you have a gene mutation?
  • Who you would like us to share your result with?

Research studies

Regardless of the result of your testing, there may be an opportunity for you to take part in research. Your genetics clinician or a research nurse will discuss this with you. For further information, contact a member of the research team on 020 7188 2603.

Resource number 4200/VER3
Published date March 2023
Review date March 2026

Trusted Information Creator. Patient Information Forum

Contact us

If you have any questions or concerns, please contact your genetics clinician.

Phone: 020 7188 1364 Monday to Friday, 9am to 5pm.

Cancer Genetics Service, Guy’s Regional Genetics Service
Guy’s Hospital
Great Maze Pond
London SE1 9RT

Do you have any comments or concerns about your care?

Contact our Patient Advice and Liaison Service (PALS)

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