The Role of Genetics in MS: A HealthCentral Explainer
The causes of multiple sclerosis remain unknown, but research has suggested that several environmental and genetic factors may be involved. The latter may cause people without MS to wonder whether they may “inherit” the disease or people with MS to wonder whether they may pass it down.
While scientists have not been able to conclude that MS is a hereditary disease, many studies have helped researchers better understand the relationship between MS and genetics. Here is what we know so far.
Previous studies on MS and genetics have shown that MS is influenced by family gene history. One study published in The Lancet in 1996 found that individuals who have a first degree relative with MS is 20 to 40 times more likely to develop MS than someone without such a relative. Another study published in Multiple Sclerosis in 2005 found that identical twins have a 21 percent greater chance of developing MS than do non-identical twins. These are two studies among many that have suggested a large risk of passing along MS.
A more recent study, however, has concluded that the risk of MS patients’ relatives developing the disease is lower than previously believed. Scientists from the Karolinska Institute in Sweden studied more than 28,000 individuals who were diagnosed with MS from 1968 onwards. Researchers identified biological and adopted relatives and assessed risks for developing MS. The findings, published in the journal Brain, showed that there are hereditary risks for MS, but researchers described them as “modest.” Siblings of a person with MS were found to be seven times more likely to develop the disease than the general population, while children of people with MS were found to have a five times greater risk.
As of last fall, scientists had identified a total of 110 genetic risk factors for MS—about double the number of previously identified genetic risk factors. In the study, published in the journal Nature Genetics, a team of almost 200 investigators from 13 countries worked to identify 48 new “susceptibility variants for MS” and confirmed previously identified genetic associations. These genetic variants show some sort of link to risk for developing MS, although that link is not fully understood.
The findings of this study are important because the more researchers understand the genetic risk factors for MS, the better able they will be to identify the molecular processes responsible for MS, and therefore be able to develop more effective drug treatment strategies. Researchers also said that the more insight they have into the mechanisms behind MS, the easier it will become to shut down the pathways that trigger MS in human cells.
What this means for people with MS
With study after study coming out about possible “links” and potential causes for MS, it may be challenging for people with MS to understand what the research means for them. While this may be frustrating, it can also be reassuring to know that the scientific community is invested in developing new treatments for MS and in one day finding a cure. Understanding the hereditary risks for MS and identifying genetic variants points to the mechanisms that underlie the disease and presents possible new targets for designing more effective therapies.
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International Multiple Sclerosis Genetics Consortiums (IMSGC). Beecham AH, Patsopoulos NA, De Jager P, Sawcer SJ, McCauley JL. Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis. Nature Genetics, 2013. doi:10.1038/ng.2770. Published online 29 September 2013.
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