A gene variant known to increase the risk of breast and ovarian cancer has been identified in people of Orkney descent.
A new study suggests that one in 100 people with Orkney grandparents has a specific mutation in the BRCA1 gene.
It turned out that most of them could trace their family lineage back to the island of Westray.
This is believed to be the first time a geographic ancestral link of this type has been established within the United Kingdom.
Researchers also discovered the specific variant of the Orkney gene in lower numbers in genetic testing across the UK and even the US.
Previous research has found that women from certain ethnic backgrounds, such as B. Ashkenazi Jews, also have a high rate of a particular BRCA gene variant.
Across the UK, around 1 in 1,000 people has a BRCA1 mutation, which can put women at higher risk of ovarian and breast cancer.
The BRCA genes are present in everyone, both males and females, but when one of them goes wrong, it can cause DNA damage and cause cells to become cancerous.
People with a genetic variant have a 50% chance of passing it on to their children.
Awareness of the faulty gene was raised a decade ago when Hollywood actress Angelina Jolie underwent a double mastectomy after discovering she had a BRCA1 variant.
The operation is said to have reduced her chance of developing breast cancer from 87% to 5%.
But the NHS warns that risk-reducing surgery is not the only option.
It also notes that awareness of changes in breasts, annual breast exams and MRI scans can help detect breast cancer, while lifestyle changes like healthy eating and exercise can “sometimes reduce the risk”.
There is currently no reliable screening test for ovarian cancer, she adds.
Analysis by Laura Goodwin, BBC Scotland Science and Innovation Correspondent
The identification of this variant – BRCA1 V1736A – is the result of 25 years of clinical research by Prof Zosia Miedzybrodzka, Director of the NHS Grampian Clinical Genetics Service.
At the time, the Breast Cancer Screening Center noticed that the number of families visiting them was increasing and wanted to know why.
As genetic testing increased, the team saw the same gene variant keep popping up and became suspicious of its significance.
Talking to patients about their ancestry helped establish the connection to Westray, an outer Orkney island of just 600 people.
BRCA1 V1736A probably appeared in a Westray founder individual at least 250 years ago.
To date, 37 females of Orcadian descent have been identified with the variant.
Some will never develop cancer, others have opted for risk-reducing surgery.
20 people have been found to have the gene variant who do not yet know they carry it.
They were among more than 2,000 volunteers who provided genetic data for the Orcades study (Orkney Complex Disease Study).
The study’s design at the time meant that information was not disclosed.
The team behind it has now asked permission from the Research Ethics Committee to contact the identified women to let them know they have the BRCA1 gene variant.
Prof Jim Wilson of the University of Edinburgh, who led the study, said: ‘One person here on this island had this variation in a BRCA-1 gene hundreds of years ago and now we find many descendants in both Westray as well as further afield Scotland and beyond.
“I think that’s the most significant thing I’ve ever really discovered. It will bring immediate benefits to society as a whole.”
“It is important that we know”
Former nurse Linda Hagan was born in Westray and has lived most of her life there.
Her parents and grandparents and most of her ancestors were also from the island.
Linda, 69, told the BBC her younger sister died of breast cancer four years ago.
She should have the results of her genetic screening shortly.
Linda has three daughters and said it was hard to imagine she could have passed the gene variant on to them.
“But it’s important that we know and hopefully something can be done about it,” she said.
Grandparents from Westray
The latest research from the Universities of Aberdeen and Edinburgh has been published in the European Journal of Human Genetics.
The study looked back at the 80 grandparents of BRCA1 variant carriers identified in the Orcades genetic study and found that 60% were from Westray.
Other ancestral links to the island date back to the early 18th century.
Orkney’s population is just 22,000, but there are people with a common ancestry around the world and the researchers said they should be offered a targeted test for the variant.
The test is currently available in Scotland for those who know of a direct family link to the gene or have a family history of ovarian or breast cancer.
Planning is underway for a small pilot that will offer testing to anyone living in Westray with a Westray-born grandparent, regardless of family history.
If the pilot is successful, the long-term aim is to offer the test to anyone in Scotland with a Westray-born grandparent who wishes to do so.
The NHS Grampian Genetics Clinic operates a helpline for questions about the gene variant linked to breast and ovarian cancer for those who have Orkney grandparents. The number to call is 01224 553940. Email inquiries can be directed to gram.orkBRCAgene@nhs.scot
GPs cannot assist with genetic testing and any questions about this research and next steps should be directed to the hotline.