IZ7RA and IL2RA are proteins that guide the actions of one type of immune cell (T cells). As genes control how proteins are made in the body, changes in protein type represent a difference in genetics.
The MS-related version of the protein may contribute to MS by guiding those immune cells to attack the nervous system, which leads to demyelination and lesions on the brain and spinal cord. This damage, in turn, causes the huge variety of MS symptoms. Interestingly, IL2R mutations have been associated with type 1 diabetes and Graves’ disease, also autoimmune disorders.
What Does This Really Mean?
"Scientists have found two genes for MS.” I'll try to shed some light on this. The statement is confusing, as it implies these genes "cause" MS in the same way that certain genes directly cause birth defects or other problems. This is misleading. Instead of a direct causal link, the "MS genes" work to increase susceptibility to MS, meaning that other factors are still at work. This just means that certain people with these genes are 20 to 30% more likely to have MS. Put it this way: If the overall risk of MS in the United States is 1 in 1000, and you have these genes, your risk becomes 1 in 770.
Why Is This Important?
One reason is that further understanding the MS disease process may generate new ideas for treatment. These newly discovered genes cause a defect in certain proteins that regulate immune system activity. If we could "fix" these proteins or counteract their actions, we might be able to stop the T cells from attacking our central nervous system. Only a tiny percentage of people with these genes develop MS (about 1 in 770, or 0.13%). Other factors still seem to be required to "activate" these genes.
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Source: International Multiple Sclerosis Genetics Consortium, Hafler DA, et. al. Risk alleles for multiple sclerosis identified by a genomewide study.
N Engl J Med. 2007 Aug 30;357(9):851-62. Epub 2007 Jul 29.
International Multiple Sclerosis Genetics Consortium, Hafler DA, et. al. Risk alleles for multiple sclerosis identified by a genomewide study. N Engl J Med. 2007 Aug 30;357(9):851-62. Epub 2007 Jul 29.