A genetic variant known to increase the risk of breast and ovarian cancer has been identified in people with Orkney heritage.
A new study suggests that one in 100 people with grandparents from Orkney have a specific mutation in the BRCA1 gene.
He found that most of them could trace their family ancestry to Westray Island.
It is believed to be the first time such a geographic ancestral link has been established in the UK.
The researchers also found the specific Orkney gene variant in smaller numbers in genetic testing in the UK and even the US.
Previous research has found that even women of certain ethnic backgrounds, such as Ashkenazi Jews, have a high rate of a specific BRCA gene variant.
Across the UK around 1 in 1,000 people have a BRCA1 mutation, which can put women at a higher risk of ovarian and breast cancer.
The BRCA genes are present in every person, both men and women, but when a defect occurs in one of them it can cause DNA damage and lead to cells becoming 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 was said to reduce her chances of getting breast cancer from 87% to 5%.
However the NHS advises that risk-reducing surgery is not the only option.
She also advises awareness of breast changes, annual breast screenings and MRI scans can help detect breast cancer, while lifestyle changes such as healthy eating and exercise can “sometimes reduce the risk”.
There is currently no reliable screening test for ovarian cancer, she adds.
Analysis by BBC Scotland science and innovation correspondent Laura Goodwin
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.
Back then the breast cancer screening center started seeing an increase in the number of families seeing and wanted to know why.
As the genetic tests grew, the team saw the same genetic variant appear time and time again and became suspicious of its significance.
Telling patients about their ancestors helped establish a connection to Westray, an outer island of Orkney with a population of just 600.
BRCA1 V1736A is likely to have arisen in a Westray founder individual at least 250 years ago.
To date, 37 women of Orcadian ancestry have been identified with the variant.
Some will never develop cancer, but others have chosen to have surgery to reduce their risk.
There are 20 people found to have the genetic variant who do not yet know they are carriers.
They were among more than 2,000 volunteers who contributed genetic data to the Orkney Complex Disease Study (ORCADES).
The design of the study at the time meant that the information would not be disclosed.
The team behind it have now asked the research ethics committee for permission to contact the identified women to tell them they have the BRCA1 gene variant.
‘It’s important that we know’
Former nurse Linda Hagan was born in Westray and lived there most of her life.
His parents and grandparents and most of his ancestors were also from the island.
Linda, 69, told the BBC her younger sister died of breast cancer four years ago.
You should be receiving the results of your genetic screening shortly.
Linda has three daughters and said it would be hard to think she could have passed the genetic variant on to them.
“But it’s important that we know about it and hopefully something can be done about it,” he said.
The latest research from the Universities of Aberdeen and Edinburgh was published in the European Journal of Human Genetics.
The study looked at the 80 grandparents of BRCA1 variant carriers identified in the Orcades genetic study and found that 60% were from Westray.
Further ancestral links with the island date back to the early 18th century.
Orkney’s population is just 22,000, but there are people of shared ancestry all over the world, and researchers said they should be offered targeted testing for the variant.
Currently in Scotland the test is available to those who know a direct family link to the gene or have a history of ovarian or breast cancer in their family.
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 everyone in Scotland with a Westray-born grandparent who wants it.
The NHS Grampian Genetic Clinic runs a helpline for questions about the genetic variant linked to breast and ovarian cancer for those with grandparents from Orkney. The number to call is 01224 553940. Email inquiries can be directed to gram.orkBRCAgene@nhs.scot
Primary care physicians will not be able to assist with genetic testing and any questions about this research and next steps should be directed to the helpline.