- Researchers say faulty gene which heightens risk of breast, ovarian and prostate cancer comes from household in Whalsay, Shetland
- University of Edinburgh used data from Viking genes to trace where ‘BRCA 2’ variant came from
- Testing now offered to anyone with at least one grandparent hailing from the island, which is home to just 1,000 people
A faulty gene which can increase the risk of breast, ovarian and prostate cancer has been traced to an 18th century family in the Northern Isles.
Scientists believe the DNA segment stems from a household who lived on Whalsay, east off the Shetland mainland, before the mid 1700s.
Research led by Professor Jim Wilson, of the University of Edinburgh, used genetic data from Viking Genes, a project that concentrated on people hailing from the Orkney and Shetland Islands, to track the origins of the faulty gene variant.
And the team’s find follows a discovery last year of another type of BRCA mutation prevalent in Orkney.
Prof Wilson told the BBC: ‘This BRCA 2 variant in Whalsay, I think, arose prior to 1750.
Cancer risk genetic variant BRCA 2 was found to originate from a household on Whalsay, Shetland, in the 1700s
‘This is why these things become so common in places because many people descend from a couple quite far back in the past and if they have a cancer variant, then a significant number of people today – five or even 10 – generations later will have it.
‘It is true everywhere in Scotland, it’s just magnified in these small places.’
Testing is now offered to anyone with at least one grandparent hailing from the island of just 1,000 people and who have been affected by breast, ovarian or prostate cancer. Those with close relatives struck by the disease are also eligible.
The variant has been found to be present in one in 43 people in Whalsay while among a general sample of Shetlanders the frequency is just one in 234.
In 2023, an Orkney study discovered one in 100 people with grandparents from the archipelago carried a mutation of the BRCA1 gene with most able to trace their ancestry to the island of Westray.
The discovery prompted a pilot testing programme funded by the community.
Following the latest breakthrough, relatives of people with the known BRCA 2 variant can be genetically tested as part of standard NHS care.
The new study stated pathogenic variants in BRCA 1 and BRCA 2 ‘confer a high lifetime risk of breast, ovarian and, for BRCA 2, male breast and prostate cancer’.
It added: ‘Genetic testing for disease-associated variants in these genes in increasingly available as part of routine clinical care, to enable not only early detection and risk of reduction, but also to guide treatment decision.’
Prof Wilson told the broadcaster the medical find paved way for wider, potentially life-saving testing with other groups with known BRCA risks.
He added: ‘The Ashkenazi Jewish community have BRCA1 and BRCA 2 variants that also have a frequency of about one in 40.
‘The Ashkenazi Jewish population in England are able to take part in genetic testing for these genes but that’s not yet the case in Scotland.’