Scientists find a clue about what makes multiple sclerosis worse – The Wire Science

Representative image. Photo: National MS Society, Delaware/Flickr CC BY NC ND 2.0

An international research team has discovered the first genetic variant linked to the progression of multiple sclerosis (MS).

The team, led by scientists from the University of California, San Francisco (UCSF) and the University of Cambridge in the UK, analyzed data from around 22,000 MS patients in a genome-wide association study, which uses statistics to carefully link genetic variants to particular traits. Their results were published in the journal Nature on Wednesday.

On average, the researchers point out in the study, inheriting this variant from both parents accelerates the need for a walking stick by nearly four years compared to MS patients who did not inherit the variant from both mother and father.

The genetic variant in question lies between two genes, one of which is involved in repairing damaged cells and the other in controlling viral infections. Both of these genes are active within the brain and spinal cord.

“This is compelling evidence that whether you do well or poorly with MS is profoundly influenced by how well your brain can cope with immune system attacks” that occur as part of MS, says Stephen Sawcer, professor of neurology at the University of Cambridge and co-senior author of the study published in Nature.

Sawcer wrote his doctoral thesis on multiple sclerosis in the mid-1990s and has studied the disease extensively ever since. The identification of the genetic variant described in the art Nature study is a major advance in MS research.

“I’ve been working on it for several decades and this is the most important thing I’ve ever discovered,” Sawcer said DW extension.

What is Multiple Sclerosis?

To understand what makes the discovery of this genetic variant so unique and different from all previous discoveries in MS research requires a closer look at multiple sclerosis. It is an autoimmune disease in which the immune system mistakenly attacks the brain and spinal cord.

These attacks damage myelin, the fatty substance that surrounds and insulates nerve fibers, disrupting the nervous system’s ability to transmit signals.

These relapses, as the attacks are called, can result in a wide variety of symptoms including numbness, tingling, mood changes, memory problems, pain, fatigue, blindness or paralysis.

The severity of MS patients and the frequency with which they relapse vary greatly.

“Some patients have no symptoms, sometimes you find it post mortem and we didn’t even know they had MS,” said Sawcer, who also treats MS patients as a physician. “They can have very mild symptoms that bother them for a while and then they don’t come back for a long time. I recently had a lady who I first met 15 years ago and she’s now back with a new episode, and in the meantime she’s been having a great time. Or the symptoms can be very severe, the lady in the bed next to her was very disabled, barely able to feed herself.”

Why this genetic variant is important in MS research

All previously discovered MS-related genetic variants have helped determine the risk of developing MS. This recent is the first to give insight into where patients might fall on the spectrum of disease severity. This is important when it comes to developing treatments.

So far, there are several drugs on the market to treat the symptoms of MS relapses, but none to treat the overall progression of the disease, which means some patients will see their condition worsening faster than others.

“All drugs developed to control relapses are immunomodulators, which matches the genetics of the more than 200 variants associated with MS risk,” wrote Sergio Baranzini, a professor of neurology at UCSF and a senior co-author on the study, in an email to DW extension. “The genetics of disease severity now suggest that the central nervous system should be the target of this new class of therapies.”

Prospects of getting a ‘radically transformed’ new MS treatment

The fact that the group of patients who inherited two copies of the newly discovered genetic variant needed a walking aid in a shorter amount of time does not mean, however, that the variant can be used to make personalized predictions for individual patients. Sawcer says many more genetic variants need to be identified before this is possible, so more genome-wide association studies are needed.

However, Sawcer says that now that they can point to a specific variant associated with MS progression and know it involves genes that are normally active in the brain, drug companies are much more likely to start investing money in developing a drug that targets progression.

“The number one unmet need for MS patients is a drug, a treatment for the progressive aspect of the disease,” Sawcer said. “And the prospects for radically transforming it today.”

This article was originally posted on DW extension.

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