New Multiple Sclerosis Gene Found
Variations in the IL7R Gene May Make Multiple Sclerosis More Likely, New Studies Show
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
Variations in the IL7R gene are common, and they're more common in people
with multiple sclerosis (MS) than in people without multiple sclerosis,
according to the trio of new studies.
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
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
"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,'"
"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
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,"
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