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People born at increased risk of heart attack could be identified by a one off-genetic test, a study has found.

The Genomic Risk Score (GRS) test would only cost £40, cheap enough for population-wide screening, say the researchers.

It could help to explain why people with apparently no conventional risk factors, such as high cholesterol, can still go on to have a heart attack.

Experts say more work is needed to explore the screening idea.

Spotting risk early

GRS can be measured at any age because people's DNA does not change, so, in theory, children could be tested.

The test looks for patterns of risky genes rather than a single inherited gene.

In the study, researchers looked at blood samples, but they say the test could be done with a simple mouth swab.

They devised the GRS after analysing the genomic data from 500,000 people aged between 40 and 69, held in the UK Biobank, including 22,000 who had coronary heart disease.

Lead author Dr Michael Inouye, of the Baker Heart and Diabetes Institute and University of Cambridge, said while roughly half of coronary heart disease (CHD) is down to genetics or is inherited, the other half is lifestyle or environmental.

"We have been missing a genetic component in risk screenings... we've just been really in the dark about the genetic half."

Participants with a GRS in the top 20% were more than four times more likely to develop coronary heart disease than those with scores in the bottom 20%.

CHD is the leading cause of death worldwide and is responsible for more than 66,000 deaths in the UK each year.

Senior author Prof Sir Nilesh Samani, from the University of Leicester, said assessing people for their risk of CHD in their 40s through NHS health checks was "imprecise".

As the condition starts several decades before symptoms develop, he said there is a need to identify those at risk earlier which GRS can do.

He added it could provide a most cost-effective way of helping doctors select patients "who would most benefit from interventions, and avoiding unnecessary screening and treatments for those unlikely to benefit".

Dr Inouye said "there is still a lot of work to be done" before a test is actually deployed within any formal health care system like the NHS.

Larger and more diverse studies would also increase the accuracy of the test.

Researchers from the Universities of Cambridge and Leicester and the Baker Heart and Diabetes Institute in Australia led the study, which was part-funded by the British Heart Foundation, and is published in the Journal of the American College of Cardiology.