Association of two silent polymorphisms of platelet glycoprotein Ia/IIa receptor with risk of myocardial infarction: a case-control study

Background The platelet membrane glycoprotein Ia/IIa plays a major part in platelet function as a primary receptor for collagen. A previous report sho wed a Variation of glycoprotein Ia/IIa receptor density and function associ ated with two silent and linked polymorphisms (807C/T and 873G/A) within th e glycoprotein la gene; Because platelet thrombus formation is implicated i n the pathogenesis of acute myocardial infarction, we investigated these po lymorphisms among patients who had had a myocardial infarction. Methods We did a 2/1 case-control study including 177 patients (median age 57.0 [range 32-72] years) and 89 controls with same age and sex. Distributi ons of the 807C/T and 873G/A polymorphisms were investigated by genotyping DNA by PCR, single-strand conformation polymorphism analysis, and sequencin g. Findings The prevalence of the homozygous 807T/873A genotype was 2.9 times higher among patients with myocardial infarction than among controls (16.4% vs 5.6%, p = 0.022). There was an association between patients homozygous for the 807T/873A allele and myocardial infarction (odds ratio 3.3 [95% CI 1.2-8.8]), which was strongest in a subgroup of smokers. The homozygous 807 T/873A genotype remained an independent risk factor for myocardial infarcti on (p = 0.005) when age, sex, smoking, hypertension, diabetes, body-mass in dex, LDL-cholesterol and HDL-cholesterol, and fibrinogen were adjusted for by logistic regression. Interpretation The 807T/873A homozygosity of the platelet glycoprotein Ia/I Ia gene polymorphism, associated with differences in surface collagen recep tor density and activity, appears to be an independent risk factor for acut e myocardial infarction. Our findings need to be confirmed in a larger, pro spective study that includes patients from different populations and cardio vascular risk groups.