Scientists have traced a gene which can increase the risk of certain types of cancer back to a family living in 18th century Shetland.

Geneticists believe the gene was introduced by a family living on the island of Whalsay before 1750.

The island is situated to the east of the Shetland mainland, and is home to around 1,000 people.

Testing can be requested by people with at least one Whalsay grandparent and who have been affected by breast, ovarian or prostate cancer, or seen a close relative affected.

Christine Glaser from Lerwick is one of those who has been affected by the gene.

Last July she learned she was carrying a BRCA 2 gene variant that increased her risk of breast and ovarian cancer.

The news came as a shock, in part because the result came from a test Christine, 66, had taken almost a decade earlier.

She had been a participant in Viking Genes, a research project that looked at the genetic make up of people from the Orkney and Shetland Islands.

Since those tests were taken, the understanding of the significance of certain genes has improved and last year geneticists sought special permissions to go back to those who took part in the study to ask if they wanted to know their results.

Christine was one of them.

Although she had lost a sister to ovarian cancer, the family was unaware many of them carried a BRCA 2 gene variant that increased the risk of the disease, as well as breast and prostate cancer.

“I didn’t know what to think,” said Christine. “I got offered preventative measures so I could get my ovaries removed and I could get a mastectomy. So that’s what I did.

“When I got my ovaries removed, they checked them and there was no cancer but then I had a mammogram and they found cancer.”

Christine’s cancer was caught early and successfully treated.

Meanwhile researchers had begun to establish a pattern of where they believed the gene may have originated from.

Using the genetic data gathered in the genes study, and cross-referenced with geneticists believe they have been able to trace the gene back hundreds of years to a family living on the island of Whalsay.

Whalsay is situated to the east of the Shetland mainland, and is home to around 1,000 people.marriage, birth and death records,

Prof Jim Wilson of the University of Edinburgh led the study.

He said: “This BRCA 2 variant in Whalsay I think arose prior to 1750. This is why these things become so common in given 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.

“This is true everywhere in Scotland, its just magnified in these small places.”

It is estimated this particular variant, known as c.517-2A>G, is present in one in 43 people from Whalsay, a figure that is five-fold higher than in a general sample of Shetlanders where the carrier frequency is one in 234.

Christine’s paternal grandmother was from Whalsay. Of her five siblings, three have the gene, as does her cousin Ryan Leith, 52, which puts him at increased risk of developing prostate cancer.

“At least you can make lifestyle choices to reduce the risk,” he said. “You take an annual blood test at the doctor and that shows if there is anything abnormal showing up in the blood work. You can review your options and see if early treatment is available”

This is not the first BRCA gene variant the study has found.

In March last year, geneticists travelled to the Orkney island of Westray.

Their study suggested one in 100 people with grandparents from Orkney had a specific mutation of the BRCA 1 gene and that most of those with the gene could trace their ancestry back to the island of Westray. A pilot testing programme was launched, funded by the community.

With the Whalsay variant, genetic testing is available to relatives of people with the known BRCA2 variant as standard NHS care.

Testing can also be requested by people with at least one Whalsay grandparent and who have themselves, or a close relative, been affected by breast, ovarian or prostate cancer. Prof Wilson hopes testing will one day be offered more widely, as is the case with other groups with known BRCA risks.

He said: “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.”

Christine is well and says she is grateful she got the information when she did.

“I feel so grateful that I got that result because my next mammogram would have been in two years’ time so it could have been a different scenario. I just feel it is good that I found out I had the gene”

An event is being held in Whalsay on Thursday evening to explain the results.