Lynch Syndrome

What is Lynch syndrome?

Lynch syndrome, previously known as hereditary non-polyposis colorectal cancer (HNPCC) is an inherited condition that runs in families and increases the risk of developing bowel cancer as well as other cancers.

Lynch syndrome is the most common cause of hereditary bowel cancers and accounts for between 2-3% of all bowel cancers. Up to 75 percent of people with Lynch syndrome will develop bowel cancer at some point in their lives and the average age of developing bowel cancer is younger than in the general population (below 50).

What causes Lynch syndrome?

Lynch syndrome is caused by a pathogenic variant in one of several genes. These genes include MLHL1, MSH2, MSH6, PMS2, EPCAM and possibly MSH3. Variants in other genes such as POLE, and POLD1 may also causes characteristics which are similar to Lynch syndrome.

How do I know if I am at risk?

Individuals with Lynch syndrome usually have one of the following signs:

Bowel or womb cancer diagnosed before the age of 50
Bowel or womb cancer with tumour testing that has screened positive for Lynch Syndrome *
Several relatives with bowel, womb or ovarian cancer

Tumour testing *

NICE guidelines recommend that all womb and bowel cancer tumours should be screened for Lynch syndrome using either immunohistochemistry (IHC) or microsatellite instability (MSI) testing. A further test known as MLH1 methylation or BRAF may also be needed. If the tumour testing screens positive, then further testing on a blood/saliva sample is recommended. NHS hospitals are gradually rolling out these recommendations and therefore these tests may be performed on your/or your relative’s tumour.

If you have screened positive for Lynch syndrome on tumour testing we can arrange the appropriate genetic testing.

What will the test show?

There are three possible results:

A pathogenic variant is found in one of the genes which is known to increase the risk of breast cancer. This may change the treatment of your current cancer as well as future cancer screening
A variant of uncertain significance or VUS is identified but whether or not this is the definite cause of cancer is unknown. Most VUS are later shown not to be the cause of cancer and therefore this would not change your cancer treatment or screening.
No variant is found and the cause of your cancer is not identified. Cancer screening may still be beneficial for your relatives.

What does it mean if I have a pathogenic variant or variants?

If you have a pathogenic variant in a dominant gene or two variants in a recessive gene, this will explain why you’ve developed bowel cancer and may mean that you have an increased risk of bowel cancer and possibly other cancers in the future. Your exact risk(s) will depend on which gene mutation has been found.

You may wish to consider more extensive bowel surgery: for example, some people may have a subtotal colectomy (removal of the colon) rather than a resection if they have an increased risk in future. Some genetic variants may also alter the best type of chemotherapy.

Additionally genetic testing may indicate a risk of future cancers and therefore guide appropriate cancer screening. Depending on the specific genetic risk, different screening tests can be arranged, and risk-reducing strategies can be considered.

What are the implications for my family?

If you are shown to have a pathogenic variant it would be possible to offer predictive testing to other people in your family to see if they are also at increased risk. This testing would be free within 90 days, although individuals would need to pay for the initial consultation (£150). Alternatively, your relatives would be able to have genetic testing through the NHS.

If your test is normal we will give screening recommendations for your relatives.

Why do the prices of genetic testing vary so much?

Historically genetic testing was expensive and done by a method known as sanger sequencing, which could only look at single genes. Now we are able to look at multiple genes simultaneously using NextGeneration sequencing and therefore testing is much more affordable.

At Genetic Experts we do not add additional fees to our tests enabling us to offer them you at a more reasonable price.

How much does testing cost?

The cost for breast cancer genetic testing is £495 and insurance will usually cover this if you meet clinical criteria.

Book an initial 1 hour consultation for only £150 and find out if you are at risk and learn more.

More information about Lynch syndrome can be found under Bowel Cancer genetics

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Don’t hesitate to contact us to find out more about genetic testing and consultations

Genetic Experts UK

Email: [email protected]

Phone: 0333 339 2680

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