Australian and New Zealand scientists are a step closer to unravelling what causes multiple sclerosis.

The researchers have pinpointed two regions in the human genome which contain genes that increase a person's risk of developing the debilitating autoimmune disease.

The scientists say this may lead, eventually to being able to prevent people developing MS.

Commenting on the study, Helen Yates, Multiple Sclerosis Resource Centre Chief Executive said, "This research marks a milestone in the genetic understanding of MS. To have identified two parts of the human genome that show they have a role to play in the susceptibility of MS is a big step in the right direction for potential interventions in the disease's development."

It's a mystery why multiple sclerosis strikes healthy people when they're aged around 30, attacking the nervous system and leading to a range of disabilities including blindness and paralysis.

Scientists know genetics play a part but it's extraordinarily complex.

After scanning the DNA of more than 5,000 people, researchers from Australia and New Zealand have now identified two regions in the human genome which contain genes which increase a person's risk of developing the disease.

The research was coordinated by Dr Justin Rubio from the Howard Florey Institute in Melbourne.

"The increased risk for each gene is about 20 per cent. It seems though that together if you carry both of these genes that you are probably maybe 150 per cent more likely to get MS.", said Dr Rubio

But just because a person has those genes, doesn't necessarily mean they will develop MS.

Other factors, like viruses or environmental influences, are believed to play a part.

For a while scientists have observed that people with a vitamin D deficiency are more prone to developing MS.

Dr Justin Rubio says the new research reinforces that link

"What we've identified is a gene that's involved in vitamin D metabolism, and this we know is important in immune regulation.

So what this is saying is that something in vitamin D metabolism is important. We obviously need to do further work on this to clarify exactly how this might be occurring, but this is, if you like, an important link between genetics and the environment."

Dr Rubio says the study also casts more light on the way genes interact to start causing a person's white blood cells to begin attacking the outer coating of myelin that protects the nerves.

"For one of these genes that we've identified, one of these gene regions, provides a link between immune cells and non-immune cells. It is involved in how they talk to each other, if you like, and how they might then stimulate an immune response.

And there are ways in which this interaction can be modified.

So there's the potential development of treatments to interfere with that process."

But scientists will proceed with caution.

Professor Trevor Kilpatrick from Melbourne University also steered the research.

He says that the two regions the scientists identified are also regions of susceptibility other autoimmune diseases, like Type 1 diabetes and thyroid disease.

"What we found is that the genetic variations which predispose to MS are protective, for example, for Graves' disease and vice versa.

So when we start thinking about new generation therapeutic interventions, we'll have to be very careful about making sure that we're not inducing side effects in terms of inducing susceptibility to other autoimmune diseases."

Nevertheless, today's findings have been welcomed by organisations representing the 20,000 Australians with MS.

Jeremy Wright from MS Research Australia says now that more genes have been identified, scientists will be able to work out the mechanisms involved in the development of the MS

"It's not that each gene might multiply the chances. It's really the code's been unlocked and the chance of identifying how to test for susceptibility is now obviously close. The genes also lead to knowledge about how we can identify new therapies also."

Jeremy Wright says even though those tests or treatments may still be several years away, today's news is still an important step forward.

Sourc
Multiple Sclerosis Resource Centre