Genetic background to ravages of obesity

Why do some overweight people stay healthy (apart from possible musculo-skeletal disorders) while obesity in other individuals leads to complications like diabetes and cardiovascular disease? The explanation lies in the genes. Scientists at the Department of Clinical Sciences at Lund University in Malmö, Sweden , have identified a gene that exists in a special variant in most overweight people, a variant that makes fatty acids “leak” into the blood stream, where they don’t belong.

Fat is constantly being metabolized by the body­-being produced, broken down, and rebuilt. Adiponutrin is a protein that takes part in this process. But overweight people often have a variant of the adiponutrin gene that causes the amounts of this protein to be lower than normal.

“Adiponutrin is supposed to constitute a kind of ‘corset’ that keeps fat in its place in fatty tissue. If the protein doesn’t do its job after a sugar-rich meal, fatty acids leak into the blood instead. The high content of fat in the blood then affects the cardiovascular system, the liver, muscles, and pancreas,” explains Associate Professor Martin Ridderstråle.

The difference between obese people who are healthy and those who develop diabetes and cardiovascular disorders may be the result of their having different variants of the adiponutrin gene and some other genes, he believes. The research team in Malmö is therefore busy developing a map of genes that can show what variants of key genes function as protection and as risk factors, respectively, in connection with these diseases.

“In the future this kind of mapping of an obese patient may be of significance in treatment. Certain medications, for example, might be more appropriate for people with certain gene variants. This opens the possibility of tailoring treatment to each individual,” says Martin Ridderstråle.

The research team’s findings on the adiponutrin gene are described in an article in the latest issue of the internationally recognized journal Diabetes.