Orkney and Shetland are the focus of a new study investigating a possible genetic cause for multiple sclerosis, which is more prevalent in the far north than anywhere else in the UK, discovers Lori Anderson
THANKS to Led Zeppelin, we know what was in the minds of the Norse invaders in the late ninth century: "The hammer of the gods will drive our ships to new lands, to fight the horde, singing and crying: 'Valhalla, I am coming!' On we sweep with threshing oar, our only goal will be the western shore."
With a reputation for murder, rape and pillage, the tall, terrifying men who came on their dragonships soon became known as "Vikings" – the Old English word for "pirates". But not only did they despoil our land, they may well have left us with the legacy of multiple sclerosis (MS).
This summer, Shetland and Orkney will see another invasion – this time it will be people in white coats brandishing swabs, instead of raiders wielding axes.
A research team headed by Dr James Wilson of Edinburgh University, one of Britain's most acclaimed geneticists, seeks to discover if there is a correlation between Viking descent and cases of MS. The research will benefit not only Scots, who have a high incidence of MS, but also Scandinavia, Iceland, the United States, Canada, Australia and New Zealand.
MS is a chronic, often disabling disease that attacks the central nervous system. It is an auto-immune disease, and can eventually damage the nerve signals that control muscle co-ordination, strength, sensation and vision. While the medical cause of the disease is unknown, the reputed link between it and the dissemination of Viking genes within northern Europe keeps cropping up.
Dr Wilson and clinical fellow Dr Elizabeth Visser will be running the Northern Isles Genetic project, which is funded by the MS Society. One of their aims is to decipher whether this is indeed a Viking saga whose story is still unravelling in our genes today.
With the Shetland Isles lying 200 miles off the coast of Norway – just under two days sailing in clement weather – Dr Wilson, himself an Orcadian, says of the Norse influence on Scotland: "The Vikings who came to what is now Scotland 1,200 years ago mostly originated in Norway. They set up a powerful kingdom to all intents and purposes in Orkney and ruled over a considerable part of the north and west of the country from there.
"We can see the signature of this Norse invasion in the genes today: over half of Orkney and Shetland male lineages are Norse in origin, something over one-quarter in the Western Isles and lower percentages as you go further along the 'sea road'.
But is the high percentage of Norse genes responsible for the high rate of MS?
"That is not known, and so we hope to answer this question once and for all. It is not impossible that the genetic factors influencing MS in the Northern Isles have come from their Scottish ancestry, or even from both sources," says Dr Wilson.
The study hopes to understand why the islands have the highest rate of MS in Scotland, and probably the world.
Contributing factors may include genes, lack of sunlight, a virus or perhaps a combination of all three, or even some other as-yet unknown factor.
For their study, the team are aiming to recruit MS patients who originate in Orkney or Shetland, regardless of where they now live. A doctor will take a blood sample which the team will test for the one gene known to have a large effect on the risk of MS, and then also look for new genes.
A side product of the research will be the first accurate count of the number of people in Orkney and Shetland with MS since 1974.
"We will also be looking to see if there are any 'hotspots' within the isles, and paying attention to how many people who moved to the islands have the disease," explains Dr Wilson.
The team hope to include more than 150 people with MS in their study. There will also be a control group of people who share characteristics with the patients, but who do not have the disease.
"They may be the same age and sex and come from the same place in Orkney or Shetland as the patients, and are the group to which we will compare the patients' genes," says Dr Wilson.
The collection of blood samples and analysis will take three years, with the results being published soon after.
Another expert on the condition and its link to the Vikings is Alastair Compston, a professor of neurology and head of the department of clinical neurosciences at Cambridge University.
In a previous interview, he said: "Scotland – the mainland around Aberdeen, the Orkney and Shetland Islands – has the highest risk (of MS]. The best explanation is that this reflects the genetic background because those are areas where there is a very high influence of Nordic genes, probably delivered by the Vikings, as I understand it they were in the habit of leaving behind their genetic material in the most generous way.
"So a strong case can be made for the Vikings having distributed the illness or distributed the risk of the illness probably through their genetic material, rather than any infectious agent that they carried. Whereas in those parts of Scotland where there is more of a Celtic influence then the rates are slightly lower."
There are many diseases that are more common in one population than in others – among the population of Finland, there are more than 30 medical disorders that are almost unique to this geographical region. This is believed to have occurred as a result of the area being so isolated. This is thought to have caused a unique set of genetic abnormalities, different from those found in the rest of Europe.
This phenomenon can also be seen among populations of Ashkenazi Jews who experience a higher rate of Tay Sachs, an inherited genetic disorder.
In the past, nature and nurture were adversaries, but today scientists see that the two are linked in "switching on" a disease. Other possible causes of MS may include a lack of exposure to sunlight – and thus a lack of vitamin D – or earlier exposure to the Epstein-Barr virus.
Cynics may ask what good can come from spending three years searching the distant past for a scapegoat for a modern disease. But Dr Wilson rigorously defends the benefit the study could bring to the greater understanding of multiple sclerosis.
"The reason to look for genes involved in MS, or any other disease, is that finding the genes opens up whole new areas of research into the biology of the disease," he explains. "Knowing that a variant in a gene increases the risk of developing a disease tells you that gene is involved in the disease mechanism, in what is going wrong in the body so that some people develop the disease.
"By pinpointing the gene and the protein it codes for, we can try to fix it. If it is not working, we can try to turn it on again with a drug, or if it turned on too high, we can try to turn it down, again using a drug."
He adds: "It is all about getting a molecular understanding of what is going wrong and then designing a drug to try to intervene. Without that understanding it will be a very slow process to develop new drugs or ways of diagnosing the disease. So this project can be viewed as a first step on the long road to new treatments."
• Anyone from Orkney or Shetland who has MS (wherever they currently live in Scotland) and who is interested in volunteering can do so by e-mailing firstname.lastname@example.org or calling 0131-651 1643.
MULTIPLE sclerosis (MS) is a disabling neurological condition that currently affects around 85,000 people in the UK.
MS is an auto-immune disease, meaning that the immune system mistakes normal tissue for a foreign body, such as bacteria, and attacks it.
The disease sees the body damage its own myelin – a protective film of fatty protein that covers the nerve fibres in the central nervous system. This interferes with the messages sent from nerve endings to the brain.
Over time, the disease can also cause permanent damage to the nerve fibres, causing a gradual increase in disability.
The symptoms of the disease are unpredictable and include problems with balance and co-ordination, bladder control, fatigue, memory loss and tremors. MS can also affect speech and the ability to swallow. The disease is not terminal but has no cure, although there are many therapies used to alleviate the symptoms, including physiotherapy, drug treatment and the use of steroids to limit the impact of an attack.
Because it is a relapsing, remitting condition, symptoms can occur for a period of time before improving partially or disappearing.
It is normally diagnosed in adults between the age of 20 and 40 and is twice as prevalent in women than men. The diagnosis rate is five times higher in temperate climates – such as northern Europe and the US – than in tropical regions.
The term sclerosis comes from the Greek "skleros" – meaning hard, which refers to the tough scarring that occurs around the nerve fibres.