New genes linked to stroke risk identified

Washington: Scientists have identified new genes that predispose people to the risk of ischemic stroke, an advance that may lead to a drug target to prevent the potentially deadly and often debilitating condition.

Researchers seeking to better understand how our genes contribute to stroke risk have completed what is believed to be the largest and most comprehensive review of the human genome to identify genes behind ischemic stroke, the cause of approximately 85 per cent of all stroke cases.

An international team of scientists including those from University of Virginia (UVA) in the US examined the genomes of tens of thousands of stroke patients and far more control subjects. The research has confirmed the role of the handful of genes previously suspected, ruled out others and identified a
new gene that may become a drug target for doctors seeking to prevent the potentially deadly and often debilitating condition.

Stroke is the number two killer worldwide, and risk factors such as smoking, high blood pressure, diabetes and high cholesterol are well established. Our genes, however, also play an important role in determining our stroke risk, but relatively little is known about the inheritable risk for ischemic stroke, researchers said.

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

"We have started to alter the mortality from stroke, which is great and exciting. However, if you look at all the known risk factors, they are fairly poor at predicting an individual's risk," said Bradford Worrall from UVA. "There is some statistics that suggest as much as 50 per cent of the residual risk is unexplained, which is why understanding the underlying genetic contributors is so important," said Worrall.

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, or 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, researchers said.
The study also sheds light on the only gene that has been linked to all forms of ischemic stroke.

Researchers were able to show that the gene appears to have the strongest effect in strokes related to small vessel disease. This suggests that each identified stroke gene so far is associated with a specific stroke subtype, researchers said. The findings were published in the journal Lancet Neurology.