MONDAY, Aug. 20, 2001 (HealthDayNews) -- Men who carry a genetic variation that accelerates the formation of blood clots have double the risk of sudden death from heart disease before age 55, a Finnish study finds.
That gene, found in one of every five Caucasians, could someday be used to screen for men at high risk of sudden death, says lead study author Dr. Jussi Mikkelsson, a senior research fellow at the University of Tempere Medical School. The finding is reported in the Aug. 21 issue of Circulation: Journal of the American Heart Association.
"I think it could be part of a panel of genetic tests that could be available in seven or eight years," says Mikkelsson. "There are many other candidates for the panel, maybe 10 or 12, some of which affect blood clotting and some that affect cholesterol metabolism."
Men with the genetic variation could reduce their risk of sudden death by measures as simple as taking aspirin or another medication that reduce the likelihood of blood clots, he says.
The gene his group studied is designated HPA-2 Met. It is a variant form of a gene designated lb-IX-V, which governs the kind of glycoproteins in blood platelets. Platelets are particles that play a central role in blood clotting, and glycoproteins are molecules that enable the platelets to form clots.
HPA-2 Met appears to make platelets "stickier" so that they are more likely to form clots, Mikkelsson says. It was first identified a decade ago as a cause of abnormally low numbers of blood platelets in a form of the childhood condition called thrombocytopenia. "It has been studied in two or three studies in myocardial infarction [heart attack] survivors, but not in victims of sudden cardiac death," he says.
Mikkelsson's team conducted autopsies on 700 Finnish men who died suddenly from accidents or from a medical condition. In men under age 55, the HPA-2 Met variation was 2.2 times more common among those who suffered sudden coronary deaths, the researchers say.
Such deaths occur when the heart suddenly begins to beat irregularly and ineffectively, so that it no longer can pump blood to the body. A large blood clot that cuts off blood flow to the heart can trigger such an event, which causes death within minutes unless the person is resuscitated. Having a family member who has died of sudden cardiac death is a known risk factor for the condition. Smoking is another.
The American Heart Association says 220,000 Americans die of heart disease without being hospitalized each year, and that most of those deaths are due to cardiac arrest.
The exact role of the HPA-2 Met gene in sudden cardiac deaths is still unclear, Mikkelsson says. It could be directly involved or could be a marker for another factor associated with platelet function, he says.
Mikkelsson says, "More functionality studies are needed. We are working with other research groups in Finland to find out how it works."
He says studies have found the incidence of HPA-2 Met varies among ethnic groups, from only 5 to 6 percent in blacks to 20 percent of whites.
What To Do
The test for HPA-2 Met now is available only in specialized facilities, Mikkelsson says. Persons with close relatives who have suffered early cardiac deaths should talk to their physicians about the known risk factors for heart disease, such as blood cholesterol, blood pressure, diet and physical activity.
Information on government research into the genetic factors in heart disease is available from the National Heart, Lung and Blood Institute. Meanwhile, the American Heart Association explains heart attacks.
