New multigene test may calculate risk for youthful heart disease and other previously untestable serious illnesses

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.

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 cancers. 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.

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. 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,” says 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 make-up 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, fewer than 1 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.