Single genetic mutation can double your risk of stroke – but scientists hope discovery could lead to tailored treatments
Discovery could lead to personalised medicine where stroke treatments are tailored to individual patients

A single genetic mutation can double your risk of stroke, according to a new study.

Researchers found the gene variant increased the risk of large artery ischemic strokes, which account for over a third of all cases.

The discovery may lead to screening tests to identify those at risk along with earlier treatments and could potentially save thousands of lives.

Around 110,000 people in England have a stroke every year, while 300,000 people are living with resulting disabilities

Impact: Around 110,000 people in England have a stroke every year, while 300,000 people are living with resulting disabilities

Stroke is the second leading cause of death worldwide and a major cause of chronic disability in developed countries. The condition costs the NHS 2.8billion a year.

One of the most common types is when blood flow is impaired because of a blockage to one or more of the large arteries supplying blood to the brain, known as large artery ischemic stroke.

Researchers from St George's, University of London and Oxford University compared the genetic make-up of 10,000 people who had suffered from a stroke with 40,000 healthy individuals. The study was funded by the Wellcome Trust.

They found that an alteration in a gene called HDAC9 occurs on about 10 per cent of human chromosomes. Those people who carry two copies of the variant (one inherited from each parent) have nearly twice the risk for this type of stroke compared to those with no copies of the variant.

The protein produced by HDAC9 is already known to play a role in the formation of muscle tissue and heart development. However, the exact mechanism by which the genetic variant increases the risk of stroke is not yet known.

Professor Hugh Markus, from St George's, University of London, who co-led the study says: 'This discovery identifies a completely new mechanism for causing stroke. The next step is to determine in more detail the relationship between HDAC9 and stroke and see whether we can develop new treatments that reduce the risk of stroke.

'Interestingly, there are already drugs available which inhibit the HDAC9 protein. However, it is important that we understand the mechanism involved before trialling the effects of these drugs on stroke.'

The researchers went on to show that the new variant does not have the same effect on the risk of other types of stroke which include bleeding in the brain.

Professor Peter Donnelly, Director of the Wellcome Trust Centre for Human Genetics in the University of Oxford, who co-led the study, says: 'This is really fascinating, and if it holds up more generally, will move us closer to personalised medicine, where treatments and preventions can be tailored more precisely to individual patients.'

The study was published online in Nature Genetics today.