Scientists reveal origin of cancer risk gene was 18th century family from remote Scots island

A defective gene that can increase the risk of breast, ovarian and prostate cancer cancer can be traced back to an 18th century family in the Northern Isles.

Scientists believe the DNA segment comes from a household that lived on Whalsay, east of mainland Shetland, before the mid-18th century.

Research led by Professor Jim Wilson of the University of Edinburghused genetic data from Viking Genes, a project focused on people from the Orkney and Shetland Islands, to determine the origins of the faulty gene variant.

And the team’s find follows last year’s discovery of another type of BRCA mutation common in Orkney.

Professor Wilson told the BBC: ‘I think this BRCA 2 variant in Whalsay originated before 1750.

The cancer risk genetic variant BRCA 2 was found to have originated from a household in Whalsay, Shetland in the 18th century

‘This is why these things are becoming so common in some places, because many people are descended from a couple far back in the past and if they have a variant of cancer, then a significant number of people today – five or even ten generations later also have this. .

‘It’s true all over Scotland, in these small places it’s just magnified.’

Testing is now offered to anyone with at least one grandparent from the island of just 1,000 inhabitants who has been affected by breast, ovarian or prostate cancer. Those with close relatives affected by the disease are also eligible.

The variant appears 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, a study in Orkney found that one in a hundred people with grandparents from the archipelago carried a mutation of the BRCA1 gene, allowing most to trace their ancestry to the island of Westray.

The discovery prompted a community-funded pilot testing program.

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 that pathogenic variants in BRCA 1 and BRCA 2 “contribute a high lifetime risk of breast, ovarian cancer and, for BRCA 2, breast and prostate cancer in men.”

It added: ‘Genetic testing for disease-associated variants in these genes is becoming increasingly available as part of routine clinical care, to not only enable early detection and risk reduction, but also to guide treatment decision.’

Professor Wilson told the broadcaster that the medical finding paved the way for wider, potentially life-saving testing with other groups with known BRCA risks.

He added: ‘The Ashkenazi Jewish community has BRCA1 and BRCA 2 variants that also have a frequency of about one in 40.

‘The Ashkenazi Jewish population in England can participate in genetic testing for these genes, but in Scotland this is not yet the case.’