Scientists discover a new gene linked to stroke

Researchers have discovered a gene linked to the risk of stroke that could lead to a better understanding of the devastating condition and how to prevent and treat it. The gene may also have a connection to dementia and depression, they say.

The scientists, from Boston University School of Medicine and the University of Bordeaux, in France, analyzed data on close to 85,000 people that had been collected between 1948 and 2013. About 4,300 had had a stroke.

Then they conducted a genome-wide analysis of common genetic variants associated with stroke, said study investigator Dr. Sudha Seshadri, a professor of neurology at Boston University School of Medicine.

"We looked at millions of markers in each person and said how do all the people who have stroke differ from all the people who don't have stroke in terms of these millions of markers," Seshadri told CBS News.

They identified seven known genes associated with stroke and also a new one, called FOXF2, linked to risk for all types of stroke. Specifically, it appeared to increase the risk of having a stroke due to small vessel disease in the brain, a common type of stroke.

Seshadri said that for every stroke that is diagnosed due to apparent symptoms, there are five silent strokes -- what she calls "covert strokes" -- which show up on MRI.

"More than 80 percent of these undiagnosed strokes are due to small vessel disease," she said.

No previous study has identified a gene for this common type of stroke, she pointed out; most have looked at genes linked with atherosclerosis, how platelets function and clotting processes in the blood -- risk factors for other types of strokes.

In addition to stroke, Seshadri said small vessel disease is associated with dementia risk, walking problems, depression and glaucoma, so learning about FOXF2 may help shed light on those conditions, too.

The study appears in the journal Lancet Neurology.