Murray, UT (3/06/11) – Research cardiologists at the Intermountain Medical Center Heart Institute have helped to identify 13 previously undiscovered genetic markers that are linked to coronary artery disease, which is the leading cause of death among both men and women in America.
The discovery paves the way for new research — and potentially new treatments — that may someday give new hope to millions of Americans suffering with the disease.
"The is the first major step toward a new avenue of treatment options," says Dr. Jeffrey L. Anderson, MD, one of the Intermountain Medical Center heart researchers who was part of the global effort that brought together 14 teams across two continents to participate in the study.
Findings of the study, which involved landmark worldwide genetics research involving 150 scientists and the DNA samples of over 150,000 patients from Europe, Canada and the United States will be released Sunday, March 6, in the journal, Nature Genetics.
While this far-reaching examination of human DNA enabled scientists to identify new genetic influences for coronary artery disease, they also learned that their discovery is just the beginning. It will take years – decades, even – before they fully understand how genetics and environment work together to cause heart disease.
Members of the Intermountain Medical Center Heart Institute research team include Benjamin Horne, PhD; Jeffrey L. Anderson, MD, John Carlquist, PhD, and Brent Muhlestein, MD.
Intermountain Medical Center is the only Utah center to participate in the study.
“What we learned is that coronary artery disease has multiple origins,” says Dr. Anderson. “There is not one ‘heart disease gene.’ There are 23 genetic markers – 10 that we were previously aware of, and now 13 others that we’ve uncovered – that we consider significant, and each one of them only plays a modest role in heart disease. It’s our job, now, to determine the interaction among those markers.”
Benjamin Horne, PhD., director of genetic and cardiovascular epidemiology at Intermountain Medical Center, and principal investigator of the study for the Utah team, points to one single nucleotide polymorphism, or genetic marker, as an example. It is located on chromosome 9p21. Scientists have determined that 9p21 is perhaps the most influential SNP for coronary artery disease. However, the area on the chromosome – its “neighborhood” on the chromosomal map – doesn’t code for any specific gene or previously known function. So it raises the question: What does it do? Right now, they believe it is a regulator of other genes. Determining which ones it regulates, and how, is the key.
“When we have that answer, we will hopefully have new insights into the workings of the body,” says Dr. Horne. “And that information will ultimately lead to new treatments that were previously unavailable simply because we didn’t understand the biology.”
The human genetic code contains over three billion pairs of letters in the DNA alphabet. Previous, smaller studies had isolated 10 of the 23 genetic markers associated with coronary artery disease. Spotting an additional 13 markers among the one million they researched was difficult. A large patient sample was needed to show patterns in such tiny bits of information.
Thousands of Utahns participated in the study through the Intermountain Healthcare cardiovascular database, one of the largest heart DNA databases in the world, which puts Intermountain Medical Center at the forefront of cardiovascular genetic research.
The CARDIoGRAM consortium collected DNA samples from over 85,000 patients of European ancestry in 14 different studies. That data collection was then compared to another 60,000-plus patients in order to validate the original findings. About 10 percent of the participants in that validation group were Utahns, both with and without coronary artery disease, who are taking part in the Intermountain Heart Collaborative Study.
“The bigger the sample, the easier it is to determine scientifically important differences,” says Dr. Horne. “People assumed in those past studies that the discovery of one or two markers would have significant effects. But that didn’t prove out because their samples were so small. This study finally makes understanding possible.”