THURSDAY, Oct. 14 (HealthDay News) -- Gene variants that increase the risk of childhood obesity have been identified by U.S. researchers.

The study authors analyzed the genomes of thousands of obese children and a control group of lean children for copy number variations (CNVs), which are deletions or duplications in DNA sequences. The CNVs they found are rare within the general population, but people with such variants are at very high risk of becoming obese, they reported.

"We found CNVs that were exclusive to obese children across two ethnicities -- European American and African Americans," study leader Struan F.A. Grant, associate director of the Center for Applied Genomics (CAG) at the Children's Hospital of Philadelphia, said in a hospital news release.

Of the 17 CNVs the investigators found in obese European American children, eight also occurred in obese African American children.

"Because many gene variants have different frequencies in different ethnic groups, detecting these same CNVs in both groups, exclusively in obese subjects, strengthens the probability that these CNVs play a genuine role in the development of obesity," co-study leader Dr. Hakon Hakonarson, director of the CAG, said in the news release.

While the findings don't have immediate applications in diagnosis and treatment, they do add to evidence that genes contribute to childhood obesity, the study authors noted.

The study findings are published in the Oct. 14 online edition of the American Journal of Human Genetics.

More information

The Nemours Foundation has more about overweight and obesity in children.