|Human Obesity Gene Map Expands|
By Nancy Touchette
Posted: June 13, 2003
Published each year in Obesity Research, the map compiles research from around the world relating obesity and genetics. This year’s update includes for the first time data from experiments in mice and rats. Some of these experiments have helped reveal human genes not previously associated with obesity.
The Obesity Map grew out of studies by Claude Bouchard, Yvon C. Chagnon, and their colleagues at Laval University in Quebec. The project now includes a Web site that maps each gene associated with obesity to a location in the genome.
Three new mutations that cause obesity are reported in the new map: mutations in two genes that code for proteins that bind the hormone melanocortin, and a new gene called Lpin1, which lowers body fat when mutated.
In addition, many genetic disorders, such as corneal dystrophy, have obesity as a complicating condition. The Obesity Map includes 37 such syndromes.
Obesity most often involves a combination of environmental and genetic factors. Most genes on the map fall into three categories: those that affect appetite; those that affect overall metabolism; and those that regulate the way fat is stored in the body.
“Usually what we see is a bad genetic package made worse by our way of life,” says Chagnon. “When you have easy access to food and don’t burn what you eat, obesity results.”
Unfortunately, the genome has not yet revealed a cure for obesity. “There are no miracle pills,” says Chagnon. Perhaps the only cure is to burn off more calories than you take in.
Bouchard, now at the Pennington Biomedical Research Center in Baton Rouge, Louisiana, and his colleagues also publish an annual review of research related to genes and physical fitness. Their gene map for performance and health-related fitness is to be published in August.