‘Obesity genes’ identified among people with African ancestry

April 15, 2013
 
The largest genetic search for “obesity genes” in people of African ancestry has led to the discovery of new regions of the human genome that influence obesity in these populations and others.
The study, “A meta-analysis identifies new loci associated with mass index in individuals of African ancestry,” was published online April 14 in the journal Nature Genetics.Led by researchers at the University of North Carolina’s Gillings School of Global Public Health and the University of Southern California’s Keck School of Medicine, the study was a collaboration of hundreds of scientists worldwide.

Dr. Kari North

Dr. Kari North

“What we found in this study sheds new light on the genes that can influence obesity,” said the study’s co-principal investigator Kari North, PhD, associate professor of epidemiology at the Gillings School. “This included discovering three new genetic variants that not only are associated with body mass index (BMI) in populations with African ancestry, but that have implications for other populations, as well.”

Specifically, the study involved more than 70,000 men and women of African ancestry. Within that population, researchers were able to identify three new genetic variants, known as single nucleotide polymorphisms (SNPs), which are associated with BMI and obesity in the sample population. Researchers found it intriguing that the SNPs are common in that population but also appear among those with no known African ancestry.

“While having these risk SNPs does not mean the individual will have a higher BMI or become obese, it does signal a predisposition,” said Christopher Haiman, PhD, professor of preventive medicine at the Keck School of Medicine. “Just to be clear, these genes account for a very small fraction of the differences in BMI noted between individuals in the population. Poor diet and reduced physical activity continue to be the main driving forces for obesity.”

However, North says, these genes are indicators of unique biological processes that may lead to increased BMI and obesity. Importantly, their identification could in the future lead to the development of medicines to reduce or even prevent obesity.

“It’s an important finding,” North said. “It provides substantial evidence that genes can influence obesity and that this genetic predisposition is likely shared across populations. The research also opens the door for more genetic studies in this area and for examination of other potential shared traits in diverse populations.”

Other study co-authors from the University of North Carolina at Chapel Hill include Mariaelisa Graff, PhD, postdoctoral associate in epidemiology; Joanne Jordan, MD, MPH, Joseph P. Archie Jr., Eminent Professor of medicine and director of UNC’s Thurston Arthritis Research Center; Leslie Lange, PhD, research associate professor of genetics, in the School of Medicine; Youfang Liu, MD, PhD, research assistant professor of genetics, Thurston Arthritis Research Center and School of Medicine; and William Maixner, DDS, PhD, Kenan Distinguished Professor of endodontics and director of the Center for Neurosensory Disorders, in the School of Dentistry.

 
When the study was conducted, Keri L. Monda, PhD, was a research associate professor and Sarah Nyante, PhD, and Kira C. Taylor, PhD, were postdoctoral associates, all in the Gillings School of Global Public Health’s epidemiology department.The complete study can be found in Nature Genetics.

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Gillings School of Global Public Health contact: David Pesci, director of communications, (919) 962-2600 or dpesci@unc.edu.