Scientists identify common genetic variant that increases risk of stroke

A study by an international research team, published a study this week in The New England Journal of Medicine, identifies for the first time a genetic variant that leads to an increased chance of stroke.

Stroke is the third leading cause of death in the US and, while it has been suspected that genetics plays an important part in increasing the risk of stroke, this study has taken an important step towards understanding the specific genes that contribute to the disease.

Eric Boerwinkle, a geneticist at The University of Texas Health Science Center and one of the lead authors of the paper, said that they had discovered two variants on chromosome 12 near genes that are implicated in stroke. One of these genes is associated with controlling blood pressure and the other is linked to brain injury and repair.

The study was carried out on 18,058 individuals from Europe and America and included people of both white and black ethnicities. It was found from the data collected that about 20 per cent of white participants and 10 per cent of black participants have at least one of the genetic variants that lead to the increased risk of ischemic stroke. Ischemic strokes are caused by a blockage preventing blood from entering the brain and account for 90 per cent of all strokes.

Dr Philip Wolf, a neurologist at Boston University and another of the study's lead authors said 'Identification of genes predisposing to stroke may aid in the identification of persons at increased risk of stroke in whom particularly vigorous attention to preventative measures can be applied'.

However, Dr Walter Koroshetz, deputy director of the US National Institute of Neurological Disorders and Stroke, said that the findings presented in this study were not decisive enough to change the current strategy used for stroke prevention. In addition to this Dr Koroshetz said that the results of the study 'will lead scientists to direct their attention to new important biologic mechanisms and hopefully new treatments to prevent stroke'.

Boerwinkle emphasised that, while the study has made important developments in our understanding of the genetic factors associated with stroke, the impact of environmental factors such as smoking remain significant. '[The gene variant] has a modest effect on stroke risk... therefore everyone, whether they carry this variant or not, should be aware of the risk factors of stroke, such as high blood pressure and smoking, and do everything you can to avoid those risk factors,' he said.