identifies new genes linked with MS
Jul 29, 20071:04PM EDT
(Reuters) – After decades of dead ends, scientists have identified two genes
that may raise the risk of multiple sclerosis, lending insight into the causes
of the debilitating disease.
findings, released in two medical journals on Sunday, represent the first genes
conclusively linked to multiple sclerosis in more than 20 years, experts
is a disease of the central nervous system that affects about 350,000 people in
the United States and more than 2.5 million people globally.
a large-scale study appearing in an online version of the New England Journal
of Medicine, teams of international researchers scanned the entire human genome
of more than 12,000 people for MS risk factors.
study uncovered two new gene suspects, both of which are thought to play a role
in autoimmune disease.
now, the only genetic link identified with MS was the major histocompatibility
complex, or MHC, a large cluster of genes essential to the immune system.
of the newly discovered genes appears to be as instrumental to developing the
disease as MHC, but the research is important because it lends insight into other
genetic factors that raise a person's risk of multiple sclerosis.
this genetic road map will be of incredible importance in developing new
therapies, said Dr. David Hafler of Harvard Medical School, who
worked on the genome study.
The role of one of the gene suspects in MS --
a variant of the interleukin-7 or IL-7 receptor -- was confirmed in two papers
published online on Sunday in Nature Genetics.
gene helps control the activity of regulatory T cells, which suppress the
activation of the body's immune system.
discovery brings us into a whole new pathway that could have a very important
role in understanding the fundamental mechanisms that trigger MS,
said Dr. Stephen Hauser, professor of neurology at University of California San
Francisco, who worked on studies released online in the New England Journal of
Medicine and Nature Genetics.
the studies used different methods, they both pointed the finger at IL-7.
Nature Genetics study, led by Jonathan Haines of VanderbiltUniversityMedicalCenter in Nashville, Tennessee, and Margaret Pericak-Vance of the
University of Miami, examined variants in three genes
suspected to have a role in the disease. It found variants in IL-7 receptors
were consistently more common in MS patients than in healthy people.
observed a similar association in a separate study in Nature Genetics by Jan
Hillert of the Karolinska Institutet in Stockholm and colleagues, who looked at
a large collection of people from Denmark, Finland, Norway and Sweden.
other gene identified by the whole genome scan -- the IL-2 receptor -- has been
linked to two other autoimmune diseases: type 1 diabetes and autoimmune thyroid
story here is the commonality of autoimmune disease, Hafler said.
believe both environmental and genetic factors play a role in the development
of MS, which attacks and destroys the insulation along nerve fibers.
symptoms range from mild muscle weakness to partial or complete paralysis.