Gene variants 'raise risk of childhood obesity'

Washington, Oct 17 (ANI): Genes have a strong influence on childhood obesity, according to a new study by pediatric researchers.

The study team searched across the whole genomes of thousands of obese children for copy number variations (CNVs)--deletions or duplications of DNA sequences.

Although the CNVs they found are rare within the population, their data suggest that those individuals harboring such variants are at a very high risk of becoming obese.

"Our study is the first large-scale, unbiased genome-wide scan of CNVs in common pediatric obesity," said study leader Struan F.A. Grant, Ph.D., associate director of the Center for Applied Genomics (CAG) at The Children's Hospital of Philadelphia.

"We found CNVs that were exclusive to obese children across two ethnicities-European Americans and African Americans."

In the current study, the researchers searched for CNVs in a European American cohort of 1,080 obese children and a control group 2,500 lean children. The obese children were in the top 5th percentile of body mass index, but to avoid confounding their data, the researchers excluded the most severe cases, many of whom were likely to have complicated medical syndromes.

After identifying multiple CNVs occurring in the obese children but not the lean controls, the researchers replicated the study in a different cohort, all African American children: 1,479 obese subjects and 1,575 lean controls. All the children were between ages two and 18, recruited from The Children's Hospital of Philadelphia pediatric network.

Of the 17 CNVs they found in obese European Americans, eight, or nearly half, also occurred in obese African Americans.

"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 Hakon Hakonarson Hakonarson said.

The study appears online in the American Journal of Human Genetics. (ANI)