The findings are just the beginning, said Jeffrey L. Anderson, a cardiologist at the Intermountain Healthcare hospital. "There is not one 'heart disease gene.' There are 23 genetic markers that we consider significant, and each of them plays only a modest role in heart disease. It's our job now to determine the interaction among those markers."
The study, published Sunday in Nature Genetics, was led by researchers at the University of Leicester in the United Kingdom and University of Lubeck in Germany, but also involved 150 scientists from across Europe, Canada and the United States.
The consortium began with an analysis of 14 previous studies based on the complete genetic profiles of more than 85,000 people of European descent with heart disease. To validate the findings, researchers then compared the data to the data of about 60,000 new heart patients, about 10 percent of whom were Utahns who volunteered to have their DNA collected and stored in Intermountain Medical Center's cardiovascular database.
Such far-reaching analyses of human DNA only recently became possible, said Benjamin Horne, director of genetic and cardiovascular epidemiology at Intermountain. "Four years ago, the way we did genetic research was we would look for a candidate gene suspected to have some biological function."
But sample sizes were in the thousands and hunting for one gene among 3 billion base pairs was like hunting for a needle in a haystack, Horne said. Now researchers can analyze millions of genes and look for genetic markers, or gene regions that influence disease.
With this study, technology enabled the team to find 10 genetic markers that appear to contribute to heart disease independent of traditional risk factors, such as high cholesterol and blood pressure, diabetes, smoking and obesity.
"We don't yet understand their function," said Horne, postulating they could be regulators of other genes, controlling which genes are expressed.
Anderson cautions this doesn't lessen the importance of living a healthy lifestyle.
"It's been determined that 40 to 50 percent of the risk for heart disease is genetically based," he said. "But the genetic markers identified so far only account for 20 percent of the genetic risk and 10 percent of the overall risk."
It will take years, even decades, for scientists to understand how genetics and the environment work together to cause heart disease, Anderson said. "We're not going to find any more big [genetic] players. … But soon, we'll be able to analyze the entire human genome and shift our focus to less common variants that have a strong influence."