MELBOURNE, May 28 (UPI) -- Several genes appear to be linked to heart attacks and scientists are now trying to identify the individual genes and how they operate, Australian researchers report.
Writing in the journal Arteriosclerosis, Thrombosis and Vascular Biology, the team said the genes are probably involved in causing the buildup of cholesterol-containing plaque in arteries and the formation of blood clots that block coronary arteries.
"At present, we can explain only about one half of heart attacks as being due to high blood pressure, cholesterol, diabetes, smoking and the like," Stephen Harrap, principal investigator and head of the department of physiology at the University of Melbourne, told United Press International.
"The genes (we discovered) may amplify these risk factors but they may also explain why apparently fit, healthy individuals drop dead from heart attacks," Harrap said.
Previous genetic studies have looked for genes related to risk factors for heart attacks such as narrowing of the arteries, high blood pressure and cholesterol levels. This is the first study to examine the possible direct genetic causes of heart attacks, defined as clotting of blood in the arteries directly connected to the heart, which deprives the heart muscle of oxygen.
Harrap's team scanned the genome of 61 pairs of brothers and sisters who had experienced heart attacks before the age of 70 to look for similar regions of DNA.
They identified "three regions on separate chromosomes linked with heart attack," he said. "The findings tell us where genes predisposing to heart attack are likely to exist but it does not tell us the exact nature of the gene or the changes in the DNA sequence that might be responsible," Harrap told UPI.
The scientists hope the finding will lead to more effective methods of preventing and treating heart attacks. "This may come in the form of drug therapy or hopefully simple, cheap, safe and effective lifestyle and dietary measures," Harrap said.
Stephen Mockrin, director of the division of heart and vascular diseases at the National Heart, Lung and Blood Institute in Bethesda, Md., told UPI the findings "open up new doors for diagnosis (of heart disorders) and could lead to new targets for drug therapy."
"It might help determine which drug is most effective ... and may be able to tell who is at the greatest risk for heart attack and what kinds of prevention strategies they would have to take," Mockrin added.
Harrap said the study might also "reveal previously unknown genes that predispose to heart attack in ways we have never considered."
The technique they used "may have missed 400 other genomic regions" related to the heart, Mockrin said, adding "there may be 100 or 200 genes" in the three regions they identified.
This may be the tip of the iceberg for genes involved in heart disorders, Mockrin noted. There are "lots of studies coming out now" looking at genes related to heart attacks and other heart problems, he said.
(Reported by UPI Medical & Health Correspondent Steve Mitchell in Washington)