Study finds genetic link in high blood pressure for African-Americans

The study, “Genome-wide association analysis of blood-pressure traits in African-ancestry individuals reveals common associated genes in African and non-African populations,” was published online Aug. 22 in The American Journal of Human Genetics.

Dr. Franceschini

Nora Franceschini, MD, MPH, research assistant professor of epidemiology at UNC’s Gillings School of Global Public Health, Xiaofeng Zhu, PhD, professor of epidemiology and biostatistics at Case Western Reserve University School of Medicine, and more than 100 international investigators co-led the study, which included nearly 30,000 Americans of African descent.

“This is the largest discovery study for blood pressure genes ever done in individuals of African ancestry, and it results from a multi-center collaboration among investigators of the U.S., Europe and Africa,” Franceschini said. “U.S. individuals of African ancestry have a disproportionally higher prevalence of high blood pressure compared to other populations. The increased susceptibility to hypertension is thought to be in part due to genetic effects, and it accounts for increased risk for coronary heart disease, stroke and kidney failure in African-Americans.”

Franceschini and colleagues discovered four novel gene variations and confirmed multiple previously reported genes that increase risk of hypertension in this population. The researchers also found that this set of genes influences blood pressure across ethnic populations. The meta-analysis involving 19 sites also successfully identified additional genetic variations in those of European ancestry.

“Non-European ancestry populations have been understudied in genetics although they likely could have a greater benefit from discovery of genes related to blood pressure,” Franceschini said. “We were able to identify new genetic variants associated with blood pressure and show that they are also relevant to other ancestry populations.”

Researchers estimate that as much as 40 percent to 50 percent of the general population’s susceptibility to high blood pressure is a result of genetic make-up. Other factors known to be associated with the disease include lifestyle, diet and obesity. Compared to Americans of European ancestry, African-Americans’ increased hypertension severity contributes to a greater risk of stroke, coronary heart disease and end-stage renal disease.

The study was conducted by the Continental Origins and Genetic Epidemiology Network (COGENT) consortium and comprises the largest genome-wide association study of blood pressure in individuals of African ancestry to date.

“The ultimate hope is to find targets for therapy in addition to developing a better understanding of pathways leading to hypertension and learning more about how genetic susceptibility to hypertension can be modified by environmental context, for example, lifestyle and a low-salt diet,” she said.

Franceschini will present her findings at the annual meeting of the American Society of Human Genetics on Oct. 22 in Boston.

Gerardo Heiss, MD, PhD, Kenan Distinguished Professor of epidemiology at the Gillings School, Yun Li, PhD, assistant professor of biostatistics at the Gillings School and assistant professor of genetics in the School of Medicine, and Quing Duan, PhD, research assistant in bioinformatics at UNC are also co-authors on the paper.