What are the risk factors for MS?

Hannah - So, Campath offers some hope to multiple sclerosis sufferers, but might it be possible to entirely cure the disease in the future for all those that have MS? Steve Hauser is a Neurologist at the University of California in San Francisco and he joins us now. Hi there, Steve.

Steve - Good evening.

Hannah - So, MS can manifest itself either gradually or it can comeon more suddenly as we heard in Anthony's case, but how does this quite broad spectrum of the way that MS can work, how does this affect treatment and also management?

Steve - Yes, this is a very important point that you've just made. MS like other chronic autoimmune inflammations, rheumatoid arthritis for example, can be a benign, almost trivial illness in some people and a very aggressive and life-changing illness in others.

So, the first important consideration is that the severity of MS is very broad. The second important point is that the important outcomes can play out, not only over a year or two, but much more often over a decade or two, or longer. Our experience with therapies generally involved just 2 years or at most, 3 years of observation. So, it's an inadequate window to really see the long term outcomes that we all care so much about.

For someone like Anthony who began with numbness in a couple of fingers, we really want to know what the natural course is. We want to be able to predict the future in those individuals so that we can assess whether this will be a serious or a trivial problem. And also, how aggressively we would want to treat.

Hannah - Alastair was talking about the immune system kind of attacking the nervous system. Is that genetics that are involved in this? So, for example, did Anthony have a genetic predisposition to this immune system hyperactivity?

Steve - Well, most likely, he does. But in general, the genetic architecture of multiple sclerosis is quite complex. This is not a simple genetic disease as Huntington's disease is, for example, but is a problem where many different genes, most of which influence somehow the function of the immune system, work together to increase one's risk. However, most of the risk we believe is environmental. So, this is a complex problem in which both genes and environment participate.

Hannah - And what type of environmental factors are involved?

Steve - Well, we don't have a full understanding of those. We do believe that the disease has increased in frequency over the past 100 years and that is certainly environmental and not genetic because our genes don't change enough over just a few generations to account for this. We believe that vitamin D insufficiency, that most people in the Western world have chronically, is part of the story. A healthier, cleaner environment, perhaps with later exposure to the Epstein-Barr virus, might be another part of the story. And then there were some other associations that may not be causal but that are related to one's risk of multiple sclerosis, especially smoking.

Hannah - Thank you very much, Steve. So, that was Steve Hauser from the University of California in San Francisco.