http://www.iht.com/articles/2007/07/29/news/gene.php
Researchers identify gene causing multiple sclerosis By Nicholas Wade Sunday, July 29, 2007 Medical researchers have made a significant advance in understanding multiple sclerosis, a common neurological disease that causes symptoms ranging from muscle weakness to paralysis. The disease is one in which the body's immune system mistakenly attacks the electrical insulation of nerve fibers. The cause is part genetic and part environmental, but researchers trying to identify the relevant genes have endured repeated frustration. Their approach has been to guess what genes might be involved and see if patients have abnormal versions. This guesswork has produced more than 100 candidate genes in recent years, none of which could be confirmed except for long-known variants in the mechanism by which the immune system recognizes proteins that are foreign to the body. In three articles published on line Sunday in The New England Journal of Medicine and Nature Genetics, three teams of researchers say they have identified, by separate routes, new genetic variants that contribute to the disease. One team used a new advanced gene-hunting method called Whole Genome Association, which has racked up a string of successes with major diseases in the last few months. The other teams used the candidate gene approach, but because all three teams identified the same gene, the researchers say they are confident that have opened a new window into the cause and possible treatment of multiple sclerosis. The gene makes a substance called the interleukin-7 receptor, a protein that enables cells of the immune system to respond to a control agent. Researchers believe the receptor is part of a biochemical pathway involving many genes, defects in any of which may lead to the disease. It is now possible to explore the pathway, they say, in the hope of devising treatments to correct the disease-causing process. The new research is the product of several large teams at universities in the United States and abroad who have coordinated their publications and pooled their data for analysis. The leaders of the Whole Genome Association Study include David Hafler of the Brigham and Women's Hospital in Boston, Stephen Hauser of the University of California at San Francisco, and Jonathan Haines of the Vanderbilt University Medical Center in Nashville, Tennessee. The two candidate gene studies were headed by Haines and Jan Hillert of the Karolinska Institute in Stockholm. "This is a very good beginning," said Kari Stefansson of Decode Genetics, a company based in Reykjavik, Iceland, that has spearheaded the hunt for the genetic causes of common diseases. Stefansson, a neurologist, said he had studied multiple sclerosis for 20 years but had been unable to explore its genetic basis because there are too few patients in Iceland for a statistically valid analysis. Because the course of the disease is unpredictable, clinical trials are very hard to conduct. "But once you have an ironclad discovery, as I believe the interleukin-7 receptor is, then you have the motivation to endure the expense of a long clinical trial," Stefansson said. [Non-text portions of this message have been removed]
