MS: Is it all in the genes

Published on 30/07/2007 00:39

A MAJOR advance in the search for new treatments for multiple sclerosis was heralded yesterday, with news of the first genetic breakthrough in the understanding of the disease for 30 years.

In a "massive step forward" for research into MS, scientists in Britain and the United States have discovered two mutant genes which increase the risk of developing the disease by up to 60 per cent. It is hoped the discovery will lead to new treatments and help scientists understand the causes of the disease.

The findings are of huge importance in Scotland which, with 10,500 sufferers, has the highest rate of MS in the world.

MS is an auto-immune disease, meaning that the immune system attacks the patient's own tissue. It affects about 85,000 people across the UK, making it the most common disabling neurological condition among young adults.

The disease is more common in countries away from the Equator, including Britain, the US, Canada and Scandinavia.

It is thought a combination of genetic and environmental factors, such as exposure to a virus, are to blame for the disease, but scientists have yet to pinpoint an exact cause.

The latest studies, published jointly in Nature Genetics and the New England Journal of Medicine, have been possible only since the 2003 publication of the human genome - the complete blueprint of chemical sequences making up the genetic code.

This genetic map allowed researchers to scan DNA samples from more than 20,000 MS patients and volunteers unaffected by the disease.

They compared people with and without the disease, looking for subtle variations in the genes that occurred more often in those with MS.

What the teams found were two altered versions of two genes involved in the body's immune system - known as IL2R-alpha and IL7R-alpha.

Both genes make proteins that act as receiving "antennae" for molecules that help control the activity of immune-system cells, known as interleukins.

The variant IL2R-alpha has also been linked to two other auto-immune diseases - type 1 diabetes and auto-immune thyroid disease.

One of the researchers, Professor David Hafler, from Harvard Medical School in the US, said: "Scientists are increasingly finding genetic links between auto-immune diseases that affect different tissues in the body, including type 1 diabetes and rheumatoid arthritis.

"This study will likely spur further research into the connection between these seemingly separate conditions."

The latest findings represent the first genetic breakthrough in MS since the 1970s, when scientists found a link with a genetic variation called HLA-DRB1. This gene is thought to increase the risk of developing MS by up to four-fold.

Dr Simon Gregory, a researcher from Duke University Medical Centre in the US, said the search for further genetic links to MS was vital.

"Our finding is very important because the genetic factors that are already known to be associated with MS only explain less than half of the total genetic basis for the disease," he said.

Helen Yates, from the Essex-based Multiple Sclerosis Resource Centre, welcomed the new research.

"I cannot emphasise enough how important these findings are," she said. "One of the biggest concerns for people with MS is that of possible genetic implications for their children and how they might be affected.

"The more we know about the disease represents a major step forward to finding the causes of MS and new treatments."

Ms Yates said she expected the charity's helpline to be inundated with calls from MS patients asking how the new research would affect them. "We will tell them that these are very important findings, but it is not going to have an effect today, tomorrow or the next day. Nevertheless, this is a massive step forward," she said.

Dr Lee Dunster, the head of research and information at the MS Society, said: "One of the great unknowns about MS is what causes it, and this looks like a welcome breakthrough in getting to grips with the genetics behind the disease."

STAY CAUTIOUS ABOUT RESEARCH

DAVIE MacLeod has had MS for more than 25 years and is enthusiastic about new research into the disease.

"There is a lot of work going on at the moment and it is all very interesting," he said.

But the 53-year-old from Caithness said MS patients were also realistic about what new discoveries meant to them.

"What is the point of all the research if in years to come the NHS just says that any treatments created as a result are just too expensive?

"It might be better if researchers kept these findings to themselves until we know when they might turn into treatments and whether the NHS can afford them."

Mr MacLeod, support co-ordinator for his local branch of The MS Society, said it was vital that research was carried out into MS and other neurological conditions.

"This is a disease which affects an absolutely atrocious number of people in Scotland," he said.

Ms MacLeod, who has known he had MS since the age of 27, said his own diagnosis came as a shock.

"I did not think there was anything seriously wrong with me," he said. "I was suffering fatigue and tiredness. I was starting to drop things."

He now has difficulty walking and has to have painkillers or muscle relaxants to deal with his symptoms. He also gets the support of a local MS nurse.