Scientists are seeking thousands of participants for the latest phase of a study into the genetics of Orkney and Shetland.

People with at least two grandparents who were born on the islands are eligible to take part in the research, which seeks to pinpoint the links between rare genetic mutations and a range of diseases from diabetes to multiple sclerosis (MS).

The unique genetic identity of those with Northern Isles ancestry with its heavy Viking heritage offers a rare opportunity to give a detailed picture on how genes are implicated in health.

READ MORE: 'Surpise' as common bacteria in probiotic shows promise to halt Parkinson's disease 

Research published last year revealed that the island of Yell in Shetland had the highest concentration of Scandinavian genes – 28 per cent – anywhere in the world, except Scandinavia.

The VIKING II study, led by Edinburgh University, is not restricted to current inhabitants of the islands whose parents or grandparents were born there, however.

Northern Isles diaspora across Scotland, the rest of the UK and worldwide can also take part.

There are known to be substantial clusters of people descended from Shetlanders and Orcadians in Chicago, Saskatchewan in Canada, and Dunedin in New Zealand.

The researchers want to recruit 4,000 new participants for the study, which first began 15 years ago, to maximise their chances of strong results.

Lead researcher Professor Jim Wilson said: “We’ve been studying the populations in Orkney and Shetland for about 15 years now and our preliminary results show that they both have unique gene pools which have some variants that are really magnified in frequency in these parts of the world, which provides a lot of scope for us understand how these variants might influence our health.

“There are some variants that are present in Glasgow, London, Edinburgh that we don’t find here, and we find others that are much, much more common here than elsewhere.

“But we need to have sufficient samples of people with any given variant before we can make an inference about what that variant does, so it’s a very cost-effective way of looking otherwise very rare variants because they can actually be relatively common up here.

“Many of them will be doing absolutely nothing, but a subset of them will be medically important and increase risks of heart disease, cancer and other diseases.

“We want to increase the number of people we have so that we can look into these variants more effectively.”

READ MORE: Man banned from training as pilot over HIV finally takes to the sky

The team is not focusing on any one condition in particular, but some of their previous research has helped shed fresh light on puzzles such as why the populations of Orkney and Shetland have the world’s highest rates of MS.

“MS has been a bit of a conundrum,” said Prof Wilson. “We have shown that although vitamin D is important, it’s not the answer as to why there’s such an excess in Orkney.

“But common genetic variants don’t seem to be the answer either – so it’s likely it’s going to be down to even rarer genetic variants and yet again, we need more people to study rare things.”

Participants will be asked to complete an online questionnaire about their health and lifestyle, and post a saliva sample which will be used to decode each individual’s DNA.

It is also the first time in the UK that a study has been given permission to feed medical data back to patients discovered to have so-called ‘actionable variants’ – genetic mutations known to cause or increase the risk of serious disease, but where action can be taken to prevent that.

Prof Wilson said: “That could be if they had a high cholesterol variant, if they had a BRCA gene for breast and ovarian cancer, and then there are a series of much rarer things that are important to know about if you have them.

“Things like LongQT syndrome – an inherited arrhythmia that you sometimes find among lads playing football who suddenly drop down dead. It increases the risk of sudden cardiac arrest during exercise.

“Typically around two per cent of people will have one of these actionable variants but in the past its not been possible to feed these back – we’re the first study to get that permission.

“People can opt into it - they don’t have to do it.”

READ MORE: Suicidal teens in care let down by lack of inpatient psychiatric beds

Prof Wilson added that understanding genetics was the “first step” to unpicking the mechanisms of disease so that better treatments can be developed in future.

The study also involves Aberdeen University and NHS Grampian clinical genetics doctors Professor Zosia Miedzybrodzka and Dr John Dean, who have been holding clinics in Shetland and Orkney for over 20 years.

Professor Miedzybrodzka said: “Better understanding the genetics of the Northern Isles will lead to better health care in the long run, both directly to the islanders but also worldwide”.

People who would like to take part can register their interest by visiting the study website: