Study Identifies African-Specific Genomic Variant Associated with Obesity

An international team of researchers has conducted the first study of its kind to look at the genomic underpinnings of obesity in continental Africans and African Americans. They discovered that approximately 1 percent of West Africans, African Americans and others of African ancestry carry a genomic variant that increases their risk of obesity, a finding that provides insight into why obesity clusters in families. Researchers at NHGRI and their African collaborators published their findings Mar. 13 in the journal Obesity.

People with genomic differences in the semaphorin-4D gene were about 6 pounds heavier than those without the genomic variant, according to the study. Most of the genomic studies conducted on obesity to date have been in people of European ancestry, despite an increased risk of obesity in people of African ancestry.

Obesity is a global health problem, contributing to premature death and morbidity by increasing a person’s risk of developing diabetes, hypertension, heart disease and some cancers. While obesity mostly results from lifestyle and cultural factors, including excess calorie intake and inadequate levels of physical activity, it has a strong genomic component.

The burden of obesity is, however, not the same across U.S. ethnic groups, with African Americans having the highest age-adjusted rates of obesity, said Dr. Charles Rotimi, chief of NHGRI’s Metabolic, Cardiovascular and Inflammatory Disease Genomics Branch and director of the Center for Research on Genomics and Global Health at NIH. 

“Eventually, we hope to learn how to better prevent or treat obesity,” Rotimi said.