An international collaborative study including researchers from The University of Western Australia has identified at least two new gene variants that increase the risk of common childhood obesity.
The largest-ever genome-wide study of common childhood obesity was conducted by the Early Growth Genetics (EGG) Consortium and considered a broad range of children including data from the Western Australian Pregnancy (Raine) Cohort.
The current meta-analysis included 14 different research groups encompassing 5530 cases of childhood obesity and 8300 control subjects of normal weight, all of European ancestry. The study team identified two novel loci, one near the OLFM4 gene on chromosome 13, the other within the HOXB5 gene on chromosome 17. They also found a degree of evidence for two other gene variants. None of the genes were previously implicated in obesity.
Scientific Director of the Raine Cohort UWA Associate Professor Craig Pennell said the study published online in Nature Genetics was the first of its kind.
"Previous studies have focused on more extreme forms of obesity primarily connected with rare disease syndromes, while this study includes a broader range of children.
"We have identified and characterized two new genetic variants that are associated with a predisposition to common childhood obesity."
Established research indicates that obese adolescents tend to have a higher risk of mortality when they are adults. Although environmental factors, such as food choices and sedentary habits, contribute to the increasing rates of obesity in childhood, twin studies and other family-based evidence have suggested there is a genetic component as well.
Previous studies have identified gene variants contributing to obesity in adults and in children with extreme obesity but relatively little is known about genes implicated in regular childhood obesity.
"This work opens up new avenues to explore the genetics of childhood obesity", Associate Professor Pennell said. "A great deal of work remains, however, these findings may ultimately be useful in helping to design preventive interventions and treatments for children, based on their individual genomes."
The Raine Study is the largest well-characterised pregnancy cohort in the world and is conducted jointly by the UWA School of Women's and Infant's Health and the Telethon Institute for Child Health Research. The study recruited 2900 pregnant women between 1989 and 1991 prior to 18 weeks gestation at King Edward Memorial Hospital in Perth, and their children have been documented over the last 21 years.
The study "A genome-wide association meta-analysis identifies new childhood obesity loci" was funded by The National Health and Medical Research Council of Australia and the US National Institutes of Health.