| |
With obesity rates rising at an alarming speed and no good treatments, scientists have upped the ante in their search for new approaches. Now, a large international consortium has made significant headway, discovering six new genetic variants linked with body mass index (BMI), which is used to calculate obesity ranges.
The team, led by Joel Hirschhorn MD, PhD, of Children's Hospital Boston's Divisions of Genetics and Endocrinology, and researchers from the Broad Institute, the University of Michigan and institutes in Oxford and Cambridge, UK, crunched genetic and BMI data from more than 32,000 people of European ancestry, then validated their findings in an additional 59,000 individuals.
Most of the newly discovered genes hadn't before been suspected of having any role in body weight and, curiously, many are active in the brain, suggesting that differences in appetite regulation may play a role in obesity. The study, published online in Nature Genetics on Dec. 14, also confirmed two obesity-related genes that had previously been reported by other groups.
Each variant's effect on BMI was modest, but additive; Hirschhorn and colleagues estimate that the 1 percent of people carrying the greatest number of obesity-causing variants will be, on average, 10 pounds heavier than the 1 percent of people with the fewest variants, and four pounds heavier than the typical person.
This effort, though massive, is likely to have uncovered just a fraction of probably hundreds of genetic regions that each makes a small contribution to obesity, says Hirschhorn. The consortium is now performing even larger-scale studies—the hope is 100,000 or more subjects—to identify more genetic variants contributing to BMI in both adults and children. As these variants are found, at least one may well lead the way to an effective treatment.
|
|
| |
