Why Do Women Face Higher MS Risk?

by John C. Martin
Article Date: 02-04-05



Why do women develop multiple sclerosis (MS) twice as often as men
do? It's a question that hasn't been answered definitively in
scientific research. Now, doctors at the Mayo Clinic have announced
findings of recent research that delved into the differences.1 They
say their discovery could lead to better treatments for MS, helping
to minimize the tissue and nerve damage that the diseases causes.

Their report appears in the January 27 online edition of the journal
Genes and Immunity.

It Boils Down to One Thing
The scientists discovered that the gender differences that exist in
MS susceptibility may all come down to levels of a certain protein
your body produces. Women, their findings suggest, produce more of it
than men.

"How much of a protein known as 'interferon gamma' you produce
appears to be a new key variable in understanding who gets MS and who
doesn't, and especially why women develop MS more often than men,"
explained Mayo Clinic neurologist Brian Weinshenker, MD, the study's
chief author. "If you have a gene that produces high levels of
interferon gamma, it may predispose you to developing MS."

This trial was based on the knowledge that interferon gamma levels
vary between men and women.2

Genetic Distinctions Found
Working with teams of researchers from Northern Ireland, Belgium and
Italy, the Mayo Clinic group compared MS risk in four patient
populations. In studying commonalities of MS susceptibility at the
genetic level, the scientists found that men tend to carry a gene
variant that causes high levels of interferon gamma less often than
women do. "It seems as if men have a lower frequency of high
secretion interferon gamma genetic variant, and that might explain
why men are generally protected more from MS," said Weinshenker.

The researchers had theorized that this genetic variant produced high
levels of interferon gamma, which in turn, tended to promote the kind
of inflammation and tissue damage found in MS. If the variant was
overrepresented in women compared to men, it would explain at least
some of the excess MS risk in women. The discovery confirmed their
theory.

The Role This Protein Plays in MS
What exactly is interferon gamma? It belongs to a group of proteins
that communicate with cells. Research by scientists at the Cleveland
Clinic has shown that women and men naturally express different
levels of this protein.2 Other experiments found that high levels of
interferon gamma could intensify the damage caused by MS, and make
the disease worse.3 These studies formed the basis for the latest
research.

"Our finding isn't the whole genetic cause, but it's a helpful step
that could lead us to a more complete understanding of MS, and
ultimately, effective treatment," Weinshenker explained. "It's also a
very promising lead about gender differences that may pertain to
susceptibility of other diseases, too, such as rheumatoid arthritis