Genetic Variants Tied to Obesity

MONDAY Dec. 15, 2008 -- Certain people just may be destined to be obese, based on the discovery of six additional genetic variants tied to people with higher body mass index, a new study says.

The study by an international consortium, published online Dec. 14 in Nature Genetics, adds to previous research that linked two other genetic variants to obesity.

"One of the interesting things is that the genes near these variants are all active in the central nervous system, suggesting that inherited variation in appetite regulation may have something to do with people's predisposition to obesity," study leader Dr. Joel Hirschhorn of Children's Hospital Boston and the Broad Institute of Harvard and MIT, said in a news release issued by some of the consortium participants.

The study, by the Genetic Investigation of Anthropometric Traits (GIANT) consortium, concluded that each individual known variant had a small but cumulative effect on a person's BMI, a ratio of weight to height. In all, it added up to an average of 10 pounds in those with most of the variants, compared to those with the fewest. However, Hirschhorn said the researchers may have found only a handful of possibly hundreds of genetic regions that made such small contributions to one's weight, and more studies would be needed to uncover them all.

"As we learn more about what some of the genes in these regions do, we hope that these discoveries might suggest routes to new therapies for obesity," joint first author of the study, Dr. Elizabeth Speliotes of Massachusetts General Hospital, said in the news release.

Previous studies in families or twins have found that genetics account for up to 70 percent of BMI variation in the general population.

The World Health Association estimates that more than 1 billion adults worldwide are overweight, with at least 300 million of them classified as obese (having a BMI of 30 or above).

More information

The American Heart Association has more about body mass index.

Posted: December 2008


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