Fingers crossed this will lead to a better future for us all:
Multiple Sclerosis Gene Discovery First Major Genetic Advance in 30 Years
July 30, 2007 — The discovery of a new gene linked to multiple sclerosis (MS) marks the first major genetic advance in the disease in more than 30 years and may pave the way for future research and treatment options.
Two separate but related studies published online July 29 in Nature Genetics and the New England Journal of Medicine report the discovery of the interleukin 7 receptor (IL7R) alpha chain gene.
According to investigators, this is the most significant MS genetic breakthrough since the 1970s and only the second MS genetic risk factor confirmed through research.
Second Gene in 30 Years
"Although there are no immediate clinical implications, this is a great breakthrough on the research side of things. This discovery opens up an entirely new avenue of research and provides us with a new set of genes and proteins that will ultimately lead us to new targets for drug therapy and better diagnostic approaches," Jonathan Haines, PhD, principal investigator of the Nature Genetics study and senior corresponding author of the New England Journal of Medicine paper, told Medscape.
Investigators from Vanderbilt University; the University of Miami; the University of California, San Francisco; Duke University; and the University of Cambridge participated in both studies.
During the early 1970s it was discovered that a variant of the human leukocyte antigen (HLA-DRB1) was linked to increased MS risk. However, said Dr. Haines, who is from Vanderbilt University, in Nashville, Tennessee, HLA-DRB1 accounts for less than 50% of the total genetic basis of the disease.
Tip of the Iceberg?
Previously, he said, investigators were optimistic that there were only 1 or 2 more MS genes that would have a fairly large effect on MS risk. However, he said, it appears that this is not the case, pointing out that IL7R still increases MS risk only by about 20%.
"In retrospect, it now seems fairly obvious that the number of genes involved in MS is much larger than we initially thought, with each having a relatively small effect," he said.
The challenges associated with identifying remaining genetic effects in MS have been substantial. In part, he said, this has been due to the fact that the technology required to screen for specific genes across the entire genome has been available only for the past 5 years.
"We were really hampered by the tools we had available to us, but now these tools seem to be in place," said Dr. Haines.
In the Nature Genetics study, investigators used genomic convergence, which integrates multiple sources and types of evidence to select candidate genes.
In this study, a total of 7,000 DNA samples from US patients with confirmed MS and their families were compared with samples from those without the disease. A total of 28 candidate genes were identified, and of these the IL7R emerged as significantly associated with MS risk.
Clearing the Bottleneck
The investigators then replicated these findings by genotyping 2 independent northern European populations in the United Kingdom and Belgium.
In the study published in the New England Journal of Medicine, investigators from the International Multiple Sclerosis Genetics Consortium confirmed these findings using a technique known as "whole-genome association," which scans the human genome for variants associated with MS.
These researchers analyzed the association of MS with more than 330,000 single-nucleotide polymorphisms in 931 family trios that consisted of an affected person and both parents.
In addition to identifying a statistical association with the IL7R gene, the study also found a significant association with IL2R, another previously suspected MS gene.
"I think what we've done is actually gotten through a bottleneck. We've been looking for [another MS gene] for over 30 years, and we think with this breakthrough that over the next year or 2 we'll be able to identify several more genes involved in MS; this will give us a much clearer picture of what's really going on in this disease," Dr. Haines said.
The authors of the study published in the New England Journal of Medicine report no relevant financial relationships.
Nat Genet. Published online July 29, 2007. Abstract
N Engl J Med. Published online July 29, 2007. Abstract