July 30, 2007 -- Three new studies show that the IL7R gene, which affects the immune system, may affect a person's chances of developing multiple sclerosis.
The finding may eventually lead to new treatments for multiple sclerosis, researcher Margaret Pericak-Vance, PhD, tells WebMD.
"Either this gene -- the IL7R -- or a gene related to it may be an excellent target that drug companies can use to develop treatments and cures," says Pericak-Vance, who directs the Miami Institute for Human Genomics at the University of Miami.
Multiple Sclerosis Genes
Pericak-Vance worked on two of the three new studies on the genetics of multiple sclerosis.
She explains that the IL7R gene is "involved in the immune system," but that its precise role in multiple sclerosis isn't clear yet.
Scientists have worked for decades to find gene variations tied to multiple sclerosis, and that's proven to be a complex challenge, Pericak-Vance notes.
"You know how some puzzles have 500 [pieces and] some have 1,000 pieces? Well, when we started, we thought, 'OK, this is a 500-piece puzzle.' But as we did more and more research over the decades, we realized that, 'Oh my God, we really have a 1,000-piece puzzle we're trying to put together,'" says Pericak-Vance.
"It's been 20-plus years, and even though we know genes are important, we haven't been able to find them. And now, after these many years, we finally hit upon one," she says.
New Multiple Sclerosis Gene Studies
In each of the three new studies, scientists compared the genes of people with and without multiple sclerosis, and then checked their findings by studying still more people.
All in all, the studies included more than 14,000 people. Two of the studies appear in the journal Nature Genetics. The third study and a related editorial appear in The New England Journal of Medicine.
The IL7R gene stood out in all three studies. Another gene, called IL2RA, is also noted in the study published in The New England Journal of Medicine.
More multiple sclerosis genes may await discovery, notes Pericak-Vance.
She calls the IL7R gene "one of multiple genes involved in MS," and notes that scientists will study related genes and gene interactions to learn more about the genetics of MS.
But Pericak-Vance explains that IL7R gene doesn't fully explain multiple sclerosis. Environmental factors matter, too.
"There are lots of people who carry the variation that's associated with MS but don't get MS. So now we have to see what other things are involved," says Pericak-Vance.
More Work Ahead
In The New England Journal of Medicine, editorialist Leena Peltonen, MD, PhD, writes that scientists still need to find the full array of "suspicious genes" that are involved in MS. Peltonen points out that the IL7R and IL2RA genes only account for a small proportion of genetic risk for multiple sclerosis.
Peltonen works at Finland’s National Public Health Institute and University of Helsinki, as well as at the Massachusetts Institute of Technology (MIT) in Cambridge, Mass.
Still, the findings are "very significant," Pericak-Vance tells WebMD. "I think it's been a long time coming and just really opens up the possibilities for new research."
"Obviously the more we know about a disease, the more questions we have to ask," says Pericak-Vance. "But it's great that we get to ask more questions."