WASHINGTON, United States (AP) — You know your cholesterol, your blood pressure … your heart gene score? Researchers say a new way of analysing genetic test data may one day help identify people at high risk of a youthful heart attack in time to help.

Today, gene testing mostly focuses on rare mutations in one or a few genes, like those that cause cystic fibrosis or sickle cell disease, or the BRCA gene responsible for a small fraction of breast cancer. It is less useful for some of the most common diseases, such as heart disease or diabetes, because they are influenced by vast numbers of genes-gone-wrong working together in complicated ways.

Monday, researchers reported a new way to measure millions of small genetic variations that add up to cause harm, letting them calculate someone’s inherited risk for the most common form of heart disease and four other serious disorders. The potential cardiac impact: They estimated that up to 25 million Americans may have triple the average person’s risk for coronary artery disease even if they haven’t yet developed warning signs like high cholesterol.

“What I foresee is in five years, each person will know this risk number, this ‘polygenic risk score,’ similar to the way each person knows his or her cholesterol,” said Dr Sekar Kathiresan who led the research team from the Broad Institute, Massachusetts General Hospital and Harvard Medical School.

If the approach pans out and doctors adopt it, a bad score wouldn’t mean you’d get a disease, just that your genetic makeup increases the chance — one more piece of information in deciding care. For example, when the researchers tested the system using a DNA database from Britain, less than one per cent of people with the lowest risk scores were diagnosed with coronary artery disease, compared to 11 per cent of people with the highest risk score.

“There are things you can do to lower the risk,” Kathiresan said — the usual advice about diet, exercise, cholesterol medication and not smoking helps.

On the flip side, a low-risk score “doesn’t give you a free pass,” he added. An unhealthy lifestyle could overwhelm the protection of good genes.

The scoring system also can predict an increased risk of Type 2 diabetes, inflammatory bowel disease, breast cancer and an irregular heartbeat called atrial fibrillation, the team reported in the journal Nature Genetics — noting that next steps include learning what might likewise lower those risks.

It doesn’t require the most sophisticated type of genetic testing. Instead, Kathiresan can calculate risk scores for those five diseases — eventually maybe more — simply by reanalysing the kind of raw data people receive after sending a cheek swab to companies like 23andMe.