New York, Mar 1 (IANS): In what is believed to be the largest study of its kind, an international team of researchers has identified new genes that predispose people to ischemic stroke, the cause of approximately 85 percent of all strokes.

A comprehensive review of the human genome also helped the researchers identify a new gene that may become a drug target for doctors seeking to prevent this potentially deadly and often debilitating condition.

"We have started to alter the mortality from stroke, which is great and exciting," said one of the researchers Bradford Worrall from University of Virginia in the US.

"However, if you look at all the known risk factors, they are fairly poor at predicting an individual's risk. There's some statistics that suggest as much as 50 percent of the residual risk is unexplained, which is why understanding the underlying genetic contributors is so important," Worrall noted.

To advance the understanding of ischemic stroke, researchers at US National Institute of Neurological Disorders and Stroke's Stroke Genetics Network (SiGN) and the International Stroke Genetics Consortium (ISGC) conducted the massive study.

The project is believed to be roughly twice as large as any previous study investigating the genetic factors contributing to ischemic stroke.

The project examined the genomes of tens of thousands of stroke patients and far more control participants.

The findings, published online in the journal Lancet Neurology, represent the work of researchers around the world.

Ischemic stroke represents a collection of several different stroke subtypes, including strokes caused by blood clots that form in or near the heart and strokes that result from hardening of the arteries (atherosclerosis) in the head or neck.

The new gene identified by the study, for example, is thought to be associated with strokes that result from large artery atherosclerosis.

The study also shed light on the only gene that has been linked to all forms of ischemic stroke.