Two founder variants account for 90% of pathogenic BRCA alleles in Orkney and Shetland

Our research has found that one in 40 people who have four grandparents from Whalsay, one of the isles of Shetland, share the same variant in the BRCA2 gene. The variant increases the chance of developing breast, ovarian and prostate cancers.  It is six times more common in Whalsay descendants than BRCA1 and BRCA2 gene variants are in the UK mainland population.

The Viking Health Study - Shetland (VIKING I), which is part of Viking Genes, is led by Dr Jim Flett Wilson, Professor of Human Genetics, University of Edinburgh. Jim explains:

It is very important to understand that just two gene variants account for nearly all (>90%) of the inherited cancer risk from BRCA variants in Orkney and Shetland. This is in stark contrast to the situation in the general UK population, where 369 variants would need to be tested to account for the same proportion of cancer risk from BRCA genes. Any future screening programme for the Northern Isles should therefore be very cost-effective, like the NHS England Jewish screening programme.

Dr Zosia Miedzybrodzka, Professor of Medical Genetics at the University of Aberdeen and Director of the NHS North of Scotland Genetic Service, based within NHS Grampian in Aberdeen said:

Developing cancer is not solely down to carrying the BRCA2 variant, there are many complex factors, and some people with the gene variant will not get cancer. However, we know that testing and the right follow-up can save lives. Many people who carry a gene variant are unaware of it. Biological relatives of people with the BRCA2 variant are encouraged to consider being tested.

Women with the BRCA2 variant are offered MRI breast screening, usually from age 30. Some also choose prophylactic breast and ovarian surgery to significantly reduce risks. Men with BRCA2 are advised to have annual PSA blood tests from the age of 40.

An NHS Grampian genetics pilot recently demonstrated feasibility of community-based BRCA1 testing in Westray. The pilot was funded by the Westray Development Trust and funding for a wider roll out is being sought. It is hoped more testing for the Whalsay BRCA2 variant could similarly become available if funding can be secured to enable targeted community screening.  

Everyone in the VIKING I and VIKING II studies who asked for genetic results feedback and who have this Whalsay BRCA2 variant have already been sent a letter.

Comprehensive testing for all BRCA1/2 variants is already standard NHS care for everyone who develops ovarian cancer, and also those with breast cancer under 40 and prostate cancer under 50, and in some other circumstances.

People with a Whalsay grandparent with a close relative affected by breast, ovarian or prostate cancer can see if they would be eligible for an NHS risk assessment by checking the FAQs on the NHS Grampian genetics website below.

Clinical genetics service for the North of Scotland

Frequently Asked Questions – BRCA2 and Shetland

What does the latest study mean for people with Shetland ancestry?

Research done by the VIKING Genes study with the NHS Clinical Genetics clinic has found that 1 in 40 people who have four grandparents from the Shetland isle of Whalsay share the same variant in the gene BRCA2. The variant increases the chance of developing breast, ovarian and prostate cancers. 

The NHS North of Scotland Genetics Service has seen the same variant in the BRCA2 gene in several families from around Shetland with breast, ovarian and prostate cancer. Prof Jim Wilson’s VIKING I study allowed analysis of how common this gene variant is and where it came from. They found that almost all the people with the gene variant have Whalsay ancestors.

How does BRCA2 link to cancer?

We have two copies of most of the genes in our body – one from our mother and one from our father. Most breast, ovarian and prostate cancers occur by chance damage to certain genes.

However, some people inherit a variant in one copy of a particular gene that can increase their chance of developing breast, ovarian or prostate cancer.

One of these cancer predisposing genes is BRCA2, another is BRCA1. Around one in 260 people across the UK have a BRCA1 or BRCA2 gene variant that gives them a higher lifetime chance of developing breast, ovarian, and other cancers.

How are people with BRCA2 variants looked after?

Women with BRCA2 variants have a higher chance of getting breast and / or ovarian cancer. They are offered more sensitive and more frequent breast screening using MRI, from the age of 30.  They can also choose to have risk-reducing surgery, such as mastectomy and / or removal of the ovaries once their family is completed. Men with BRCA2 variants have an increased chance of getting prostate cancer and also have a small increased chance of breast cancer. Men with BRCA2 variants are offered annual blood tests to look for prostate cancer early. Many men with BRCA2 variants do not get cancer, but men and women with the gene variant can pass it onto their children.

Who can be tested for the gene variant right now?

A test is currently available to relatives of people with the known BRCA2 variant as standard NHS care.

You can also request an NHS genetic risk assessment for testing if you have at least one Whalsay born grandparent AND

(1) have had ovarian, breast or prostate cancer OR

(2) have a parent, child, sibling, nephew, niece, uncle, aunt or grandparent who has had ovarian, breast or prostate cancer.

Are there plans to expand the availability of testing?

Whilst there are no current plans, we are working towards policy change across the UK. We are also raising funds to expand the availability of screening to high-risk groups across Scotland’s island communities and their descendants across the UK. For more information on how you can help visit Support Us.

I took part in VIKING I or VIKING II and want to know if the study found I have the BRCA2 gene change. How can I find out?

All consenting individuals in VIKING I who carry this variant were sent letters in 2023 and all people in VIKING II who consented to getting results and for whom we have genetic data, were informed in 2024. If you consented to receiving actionable results from our study, and you have not received a letter from us, then you do not carry the Whalsay BRCA2 gene variant. If you are in any doubt you can get in touch with VIKING Genes at viking@ed.ac.uk for more information.

Where can I find more about BRCA2 and cancer risk?

If you know that a blood relative of yours, has been found to have the Whalsay BRCA2 gene variant and you live in Scotland, you can be considered for a test by asking your GP to refer you to your local NHS genetics clinic.

Please note, GPs will not be able to directly assist with gene testing or any questions about our VIKING I and II research.

Practical and emotional cancer support and advice is available from CLAN. More information on BRCA2 and breast, ovarian, and prostate cancer in families is available via the NHS and MacMillan Cancer Support.

Information about cancer symptoms and how to reduce your chances of getting cancer is available from the NHS Inform website. People worried that they might have cancer should read the advice on NHS Inform and consult their GP.