Milwaukee ? Zeroing in on some of the most deadly genes in human heredity, researchers at the Medical College of Wisconsin for the first time have identified a group of genes that may predispose many people to heart attacks, according to a study published today in the journal Nature Genetics.

The finding is the first big step toward developing a genetic test to gauge a person’s risk of having a heart attack.

Working with a group of 513 families of Western European descent all with histories of early heart attacks the researchers identified a region on chromosome 14 that appears to be the genetic basis for heart attacks. They estimate that 40 percent of heart attack risk is due to these genes.

The gene or group of genes on that region represent an additional risk factor needed to have a heart attack, beyond traditional risk factors such as diabetes, high blood pressure or high cholesterol.

Coronary heart disease is the leading killer in the United States, claiming about 460,000 lives a year.