Scientists find genes that could raise stroke risk

Two gene variants newly linked to stroke may increase by about 30 percent a person's risk for the third-leading cause of death in the U.S., according to a study of about 20,000 patients.

A genetic region containing the variants was implicated in more than one in 10 stroke cases, according to a study in the New England Journal of Medicine. The variants are located near the so-called NINJ2 and WNK1 genes. NINJ2 is known to be active after a nerve injury, producing a protein that helps determine how well the brain tolerates decreased blood flow, the researchers said. WNK1 is linked with changes in the severity of high blood pressure, they said.

Stroke was the top reason for serious long-term disability in the U.S. in 2008, costing about $65.5 billion in lost wages and medical treatment, according to the American Heart Association. While the risk is three times greater if a parent has had a stroke, previous studies have yielded inconsistent findings about the role of specific genes, researchers said.

"It definitely tells us something about the physiology of stroke we wouldn't have picked out alone," said Donna Arnett, a professor of epidemiology at the University of Alabama at Birmingham who wasn't involved in the study.

Arnett said the test results need to be replicated in other studies. To date, there are no commercial tests to determine if a patient has the genetic variations linked to stroke.

"You can't go to your doctor tomorrow and ask for this test," she said.