New research published in the Proceedings of the National Academy of Sciences has revealed that, at least sometimes, obesity is predetermined.

The study showed that variations in the gene ankyrin-B caused the fat cells of laboratory mice to suck up glucose faster than normal, doubling their size. Combined with an aging metabolism or high fat diet, obesity is almost guaranteed.

This gene, which might have helped store energy in times of famine, could be part of what fuels the current obesity epidemic. Present in every bodily tissue, the ankyrin-B protein tethers important proteins to the inside of the cell membrane. Defects in this gene have been linked to autism, muscular dystrophy, aging, and diabetes.

In a previous study published in the Journal of Clinical Investigation, the same Duke University-based research team noted that lab mice with cardiac arrhythmias caused by ankyrin-B mutations were fatter than their wildtype litter mates.

Further investigation by a postdoctoral fellow named Damaris Lorenzo, Ph.D. found that lab mice with variants of ankyrin-B quickly gained fat. In these mice, calories were locked away in fat tissue, rather than used as energy in other tissues.

For the current study, Lorenzo, now at the University of North Carolina at Chapel Hill, examined laboratory mice that had the ankyrin-B gene knocked out of their fat tissue only.

These mice gained weight and their energy-storing white fat cells doubled in size, even though they ate and exercised the same amount as normal mice.

Weight gain increased as the animals aged or were fed a high fat diet.

"These variants in ankyrin-B are found in about 1% of Caucasians and Hispanics and about 8% of African Americans. Therefore, mutations in this gene have a major public health implication," Vann Bennett, M.D., Ph.D., senior author of the study and George Barth Geller Professor of Biochemistry at Duke University School of Medicine, said to ALN.

"We are still in the early stages of understanding this gene, but I believe it will be helpful in our quest towards developing more personalized medicine for people."

The research team hopes to verify these findings in humans as a next step.