Sunday, February 04, 2007

Gene Variant May Predict Heart Disease, Stroke

(HealthDay News) -- Researchers have identified a gene variant associated with the early signs of heart disease and stroke in women.
None of the more than 11,000 participants in the 25-year study has yet had heart disease or a stroke, but the signs point toward increased risk, said study author Dr. Edward Lammer, a pediatrician and geneticist at the Children's Hospital Oakland Research Institute in California. The report is published in the February issue of Atherosclerosis, Thrombosis and Vascular Biology.

"We found changes in two blood vessel areas," Lammer said. "In the coronary arteries, we found calcification. We also found thickening of the carotid arteries in the neck."

A buildup of calcium makes the coronary arteries less flexible and more vulnerable to damage. Thickening of the carotid arteries, the main blood vessels to the brain, can be a prelude to a stroke.

Those changes have been seen only in women. "We have no idea why," Lammer said, although it's possible that the signs of risk will develop later in men than in women.

Now, the researchers must wait to see whether women in whom the changes have been seen run into cardiovascular trouble.

They haven't so far, probably because they are too young, Lammer said. The study began in 1971 and has followed 11,377 residents of Muscatine, Iowa, since their early teens. The Oakland researchers are working with physicians at the University of Iowa on the study.

Lammer and his colleagues measured about 100 gene variants in the study participants. One of them, designated LTC4S, has been found to be associated with a fourfold increased risk of the early signs of heart disease and stroke, after adjustment for standard risk factors such as smoking, cholesterol and blood pressure levels, Lammer said.

"What's intriguing is that the gene variant we found is involved in regulating the inflammatory response," he said. "A research group from Iceland has reported that two genes in the same pathway are risk factors for stroke. This gene generates leukotrienes, chemicals that mediate the inflammatory response."

The LTC4S gene variant has previously been associated with asthma, "which in essence is an inflammatory reaction," Lammer said. "The hope is that our early results keep the finger pointed at the role of inflammation regulation as very important for atherosclerosis, heart disease and stroke."

The fact that the link between the gene variant and the danger signs seen so far is not associated with standard risk factors could make gene testing an important part of early risk assessment for many Americans, Lammer said. "About half the people in the study appear to have this variant," he said.

Lammer and his associates are continuing to follow the people in the study to check on the incidence of heart disease and stroke associated with the gene variant.

"If it is a risk factor that is genetic, we could identify the risk factor very early in life and develop interventions, behavioral changes or medications that ameliorate the risk," he said.

More information
Background information about the genetics of heart disease is provided by the American Heart Association.

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