Millions of people carry two genetic variants that significantly increase the risk of ischemic stroke, the most common type of stroke, U.S. researchers said on Wednesday.

The study is the first to identify common genetic variants influencing stroke risk in the United States and could lead to new strategies to diagnose, prevent, and treat stroke, they reported in the online issue of the New England Journal of Medicine.

Ischemic stroke accounts for nearly 90 percent of all strokes and is caused by blockage of blood to the brain. More than 150,000Americans die from stroke every year, making it the third leading cause of death after cardiovascular disease and cancer.

In the study, the researchers, led by Eric Boerwinkle from the University of Texas, examined the DNA of about 20,000 participants,1,544 of whom developed stroke. They found two genetic variants onchromosome 12 near one gene associated with brain injury repair called NINJ2.

About 20 percent of whites and 10 percent of blacks have at least one copy of the genetic variant and each copy increases the risk of ischemic stroke by approximately 30 percent, the researchers said.

Walter Koroshetz, deputy director of the U.S. National Institute of Neurological Disorders and Stroke, which supported the study, said in a statement that the findings are "not sufficiently high to make an individual change their stroke prevention plan."

But they "will lead scientists to direct their attention to new, important biologic mechanisms and hopefully new treatments to prevent stroke," Koroshetz noted.

(Xinhua News Agency April 17, 2009)