In what is being described as a game-changing contribution to the prevention and treatment of a leading cause of adult disability in Australia, a study of more than half a million people from around the world has identified 22 new genetic risk factors for stroke.

The third highest cause of death in the nation, stroke’s sudden and catastrophic effects kill more women than breast cancer and men than prostate cancer, with one occurring every nine minutes.

But this study by members of MEGASTROKE, a large-scale international collaboration by the International Stroke Genetics Consortium, has unlocked some of the mysteries around the causes of the condition.

Researchers, including Professor Jane Maguire from the UTS Faculty of Health, were surprised by the revelation that of the 32 genetic variants – or 149 genes – identified as risk factors in the research, 11 are in biological areas not previously thought to contribute to stroke.

The study also found that drugs on the market are already targeting 16 genes in the management of other diseases such as epilepsy, providing exciting possibilities for further research into the use of medications for stroke.

“It really does open up opportunities for revisiting what we know about stroke,” Maguire said.

“When you get data like this that is discovery level that opens out our knowledge and understanding of a disease that we thought we knew so much about, it is very captivating.”

The MEGASTROKE project – the largest genetic study into the condition – analysed DNA samples from 520,000 European, North and South American, Asian, African and Australian participants, 67,000 of whom had suffered a stroke. The results were published in the journal Nature Genetics.

Strokes occur when changes occur in blood vessels, most commonly as a result of blood clots (ischaemic), while the most catastrophic are caused by bleeds in the brain (haemorrhagic). Researchers also discovered previously unknown genetic links between ischaemic and haemorrhagic stroke.

About 30 per cent of stroke survivors are of working age, with the financial cost in Australia estimated at $5 billion a year. By 2050, one million Australians are expected to be living with the effects of stroke.

Findings from the MEGASTROKE project, which also identified shared genetic influences between stroke and related vascular conditions such as coronary artery disease, deep vein thrombosis and pulmonary embolism, will contribute to improved prevention strategies and treatments.

“It is a breakthrough,” Maguire said of the findings, with the massive amount of data accumulated also likely to contribute to dramatic advances through the further study of the 11 newly identified biological pathways and pharmacogenomics research into medication possibilities.

“I would say in the next maybe even two years you're going to see even more exciting results from this sort of effort because it took a long time to actually get this data all together.”

The new insights have been made possible through stunning advancements in the genetics field since the mapping of the human genome was completed in 2003, in what remains the world's largest collaborative biological project.

For Maguire, the changes in the 11 years since the International Stroke Genetics Consortium was established have tested the limits of technology and demanded it keep pace with the rapid developments driven by scientific curiosity.

“I did my PhD on a PC using candidate work so when I joined the ISGC we all very quickly, probably after a year of us all being together, worked out that we needed servers, we needed big, big servers,” she said.

The MEGASTROKE project involved a multi-disciplinary collaborative of experts in stroke genetics from research groups in Germany, France, the UK, Japan, USA, Iceland, Spain, Switzerland, Italy, Belgium, the Netherlands, Denmark, Sweden, Norway, Finland, Estonia, Poland, Singapore, Australia and Canada.

The study received financial support from multiple sources including Australia’s National Health and Medical Research Council.




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