Obesity and high blood pressure may have something in common: the same gene mutation, says new research. But this is one mutation -- unlike many that cause disease -- that can be overcome.

Men and women who inherit two copies of the instruction tend to be fatter than those with one or no copies, according to German scientists.

However, the researchers say, fate in this case is far from set in stone: As little as two hours a week of exercise is enough to completely negate the effects of the fat-promoting gene. A report on the finding was presented today in New Orleans at a meeting of the American Heart Association.
　　The gene, GNB3 825T, is believed to increase blood pressure in people who carry it by producing a messenger protein that signals vessels to tighten up. This protein, called G, also appears to boost the production of fat cells.

That's led some scientists to speculate that the gene might be "thrift." That is, it helps carriers store energy during lean times. The trouble, however, is that while "thrifty" genes were useful when humans had to pry their food away from their environment with great effort, nowadays people struggle not to overeat, and the benefit of the gene becomes its curse.

Obesity, whether genetically based or not, is an epidemic in the United States. Recent figures show that between 1998 and 1999, the prevalence of obesity climbed from 17.9 percent to 18.9 percent of all Americans, a rise of 5.6 percent. Obesity, defined as a body mass index of 30 or more, rose among men and women of all races and socioeconomic groups. Overweight people are at increased risk of a wide range of health problems, from heart trouble to diabetes.

In the latest study, Achim Gutersohn, of the University of Essen, and his colleagues were trying to understand more about the way GNB3 825T increased heart and vessel risk in 1,291 healthy men and women. But they found that the people who inherited a copy of the gene from both their mother and father, and who didn't exercise often, were much more likely than others to be obese.

Yet even subjects with two versions of the 825T gene could avoid obesity if they worked out for at least two hours a week.

Gutersohn's group also measured the prevalence of the 825T gene across five racial and ethnic groups, including blacks from America and Africa, aboriginal Australians, as well as Chinese and Japanese.

Blacks from America had the highest prevalence of the mutation, with nearly nine in 10 carrying the gene, while whites were lowest, at less than 30 percent.

Dr. Rose Marie Robertson, a professor of medicine at Vanderbilt University in Nashville, Tenn., and president of the American Heart Association, says the finding is an important reminder of the benefits of physical activity.

"The strategies that we're already applying [to combat cardiovascular disease] seem to be effective in this case, as well," Robertson says.

The study also suggests that, as scientists uncover more of the genetic underpinnings of human life, doctors will be able to prescribe targeted treatments that best blend a person's symptoms and genes, Robertson says.

(From HealthScout)