POLYMORPHISM OF PLATELET MEMBRANE GLYCOPROTEIN IIIA - HUMAN PLATELET ANTIGEN 1B (HPA-1B PIA2) IS AN INHERITED RISK FACTOR FOR PREMATURE MYOCARDIAL-INFARCTION IN CORONARY-ARTERY DISEASE/

Conflicting results of an association between the human platelet antig en 1b (HPA-1b or P1(A2)) allele and the risk of myocardial infarction and coronary artery disease have been reported. To assess the reason f or this discrepancy, we determined the HPA-1 genotype in 298 men who h ad undergone coronary angiography, including 124 individuals with myoc ardial infarction, 83 individuals with coronary artery disease but no history of myocardial infarction, and 91 control patients. Among patie nts with acute or recent onset myocardial infarction (<1 year), the pr evalence of HPA-1b was higher than among patients with coronary artery disease but without myocardial infarction (33 percent vs. 14 percent, p = 0.016). In patients under 60 years of age this difference was eve n more pronounced (45 percent vs. 15 percent, p = 0.003). Unlike conve ntional risk factors HPA-1b does not represent a risk factor for coron ary artery disease itself but appears to be associated with increased platelet thrombogenicity.