Multiple Sclerosis (MS) Linked to Genes

Scientists have recently pinpointed genes that can predict who is more likely to get Multiple Sclerosis (MS). MS is thought to be an autoimmune disease, meaning the body attacks itself, and to date it affects approximately 400,000 Americans. Every week about 200 people are diagnosed with this potentially debilitating disease in the US alone. Although the most common image of MS is an elderly individual in a wheelchair, the first signs of disease (periods of dizziness, double vision) often appear in the late teens or early twenties, and twice as often in women. The patient may recover completely, partially, or not at all after this first “relapse” episode, and it is a lifelong disease. Most MS patients will get some permanent disability later on in their lives.

MS is a disease for which we have no cure, because scientists know very little about what causes it. Current treatment options can only modulate the disease or lessen the symptoms. There are generally two streams of thought in the scientific community on what causes the disease: it is either thought to be triggered by the environment, or it is thought that there is a genetic predisposition. Many scientists also propose both factors play a role, given the current evidence. For instance, in Japan, the adoption of a “Western” lifestyle starting in the 1950s has been correlated with a dramatic increase in the incidence of MS. Also, there are statistics showing that the further away from the equator, the higher the incidence rate of MS. It has even been proposed that Vitamin D, which our body produces with the help of sunlight, plays a protective role against MS. It would make sense then, that the sun-intensive equator regions would have a lower incidence of the disease.

Nevertheless, it is now known that genes do play an important role in predicting MS as well. A study spearheaded by researchers from Duke University have found that an important marker in the development and programming of the immune system called the Interleukin 7 alpha receptor (IL-7RA) strongly correlates with MS disease susceptibility. It is now being investigated whether this marker plays a role in causing the disease, providing a valuable clue as to how and why certain people get this illness. Despite the fact that much more research needs to be done, the study provides strong evidence that genetics are an important component, and point the research community in a helpful direction in finding a cure for the disease.

References

Gregory S et al. IL 7 Receptor alpha chain shows allelic and functional association with multiple sclerosis. Nature Genetics 2007 Sept, 39(9):1083-90.

Broadley SA. Could vitamin D be the answer to multiple sclerosis? Multiple Sclerosis 2007 Aug;13(7):825-6.

Kira J. Multiple sclerosis in the Japanese population. Lancet Neurology 2003 Feb;2(2):117-27. Review