Multigene test may find risk for heart disease, diabetes, and breast cancer

Aug. 14, 2018

You know your cholesterol, your blood pressure … your heart gene score?

Researchers say a new way of analyzing genetic test data may one day help identify people at high risk of having a heart attack at a young age 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.

On Aug. 13, researchers revealed 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.

If the approach pans out and doctors adopt it, a bad score wouldn’t mean that you’d get a disease, just that your genetic makeup increases the chance—one more piece of information in deciding on care. For example, when the researchers tested the system using a DNA database from Britain, less than 1% of people with the lowest risk scores were diagnosed with coronary artery disease, compared with 11% of people with the highest risk score.

The scoring system can also 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, Dr. Sekar Kathiresan, who led the research team from the Broad Institute, Massachusetts General Hospital and Harvard Medical School, can calculate risk scores for those five diseases—eventually maybe more—simply by reanalyzing the kind of raw data people receive after sending a cheek swab to companies like 23andMe.

A geneticist who specializes in cardiovascular disease, he hopes to open a website where people can send in such data to learn their heart risk, as part of continuing research. Kathiresan and co-author Dr. Amit Khera, a Mass General cardiologist, are co-inventors on a patent application for the system.

Other scientists and companies have long sought ways to measure risk from multiple, additive gene effects—the “poly” in polygenic—and Myriad Genetics has begun selling a type of polygenic test for breast cancer risk.

But specialists in heart disease and genetics who weren’t involved with the research called the new findings exciting because of their scope.

“The results should be eye-opening for cardiologists,” said Dr. Charles C. Hong, director of cardiovascular research at the University of Maryland School of Medicine. “The only disappointment is that this score applies only to those with European ancestry, so I wonder if similar scores are in the works for the large majority of the world population that is not white.”

NBC News has the full story