March 8, 2011 -- Three studies have identified a large number of genes linked to the development of heart disease among Europeans, South Asians, and Chinese people.
The discoveries more than double the number of genes previously associated with heart disease, the No. 1 one killer in Western countries and a major health threat in China and other parts of Asia.
The studies are published in the online edition of Nature Genetics.
In the study focusing on Europeans, the genes of more than 135,000 people were analyzed. Researchers compared healthy people with those who had been diagnosed with coronary artery disease (CAD). They found, in addition to the 10 previously known gene regions for CAD, 13 new gene regions. The findings were unexpected.
“The majority reside in gene regions that were not previously suspected in the pathogenesis of CAD,” the researchers write.
Genetics play a major role in the development of heart disease. Identifying genes that put people at increased risk could aid in the development of both prevention strategies and new treatments. But first, more study is needed to determine how the genes contribute to CAD.
“Understanding their mechanisms will not only improve our understanding of the disease process but could also ultimately help to develop new treatments,” Nilesh Samani, cardiologist and co-lead of the project from the University of Leicester in the U.K., says in a news release.
Six of the 23 confirmed genes in the study could be linked to known risk factors for CAD such as cholesterol and high blood pressure.
Europeans and South Asians Share Similar Genetic Risks
In a separate study, researchers comparing the genetic risks to CAD carried by Europeans and South Asians (primarily from India and Pakistan) found another five gene regions linked to the disease. What they weren’t able to find were risk factors unique to either population; both shared the same genetic susceptibility.
The study researchers also report that the five newly discovered gene regions play a smaller role in heart disease than the gene regions that had already been identified. They speculate that the major heart disease genes may already have been found, but that there may be many less potent -- and as yet unknown -- genes that contribute to the disease, a goal of future studies.
“Even broader collaborations would identify additional variants that influence CAD risk,” the researchers suggest.
Chinese May Have Unique Genetic Risk
The third study was a first of its kind: a genome-wide association study of Chinese, in particular Han Chinese. Like the other two studies, this one sought to identify genetic risk factors for heart disease, which kills an estimated 700,000 Chinese each year.
The research team identified a single previously unsuspected genetic risk factor, one that is not associated with heart disease in Europeans. They believe that it is possible that it might be a risk unique to Chinese, though how it works is unknown. One theory they offer is that environmental and lifestyle differences -- the two other major determinants of heart disease risk -- may explain why the gene region is triggered among Chinese but not in people in other parts of the world.
“Further studies may be needed to identify the causative variant(s) for CAD [in this gene region],” the researchers conclude.