Several platelet glycoprotein polymorphisms have been associated with an increased risk of myocardial infarction (MI) in studies that included predominantly men. In a population-based sample of 68 Caucasian women < 45 years old with non-fatal MI and 346 demographically similar control subjects, we found an increased risk of MI among women who possessed at least one copy of the glycoprotein IIb Ser843 allele compared with those lacking the Ser843 allele (odds ratio 1.85; 95% confidence interval = 1.03-3.33). The increased risk was present only in subgroups of women who smoked cigarettes, had hypercholesterolaemia or who had a family history of early onset MI. The Ser843 variant of glycoprotein IIb may be associated with an increased risk of MI in young women with other cardiovascular risk factors. Additional studies involving larger numbers of subjects are needed to confirm this preliminary finding.

Several platelet membrane glycoprotein polymorphisms have been identified as potential risk factors for cardiovascular disease. Recently a nucleotide -5T/C dimorphism in the translation initiation site (Kozak sequence) of the platelet glycoprotein Ibalpha (GPIbalpha) gene was associated with increased platelet surface levels of the GPIb-IX-V receptor complex. The role of this GPIbalpha Kozak sequence polymorphism in the occurrence of arterial thrombotic disease is unknown. We performed genotype analysis of the Kozak sequence polymorphism of GPIbalpha in a population-based study of 18- to 44-year-old women with nonfatal myocardial infarction (MI) (n = 78), nonfatal stroke (n = 106), and 384 demographically similar female control subjects. Analysis of -5T/C genotypes revealed that at least one copy of the C allele was present in 14.1% of MI cases, 23.6% of stroke cases, and 23.7% of controls. The age-adjusted odds ratio for MI in women carrying at least one copy of the C allele was 0.53 (95% confidence interval [CI] 0.27-1.05). The age-adjusted odds ratio for stroke in women carrying at least one copy of the C allele was 0.99 (95% CI 0.59-1.65). Analyses stratified by stroke type (ischemic, hemorrhagic) yielded similar results. In conclusion, young women carrying the C allele of the Kozak sequence polymorphism of GPIbalpha are not at increased risk of MI or stroke. Paradoxically, the C allele may even be associated with a reduced risk of MI in this population. This finding requires further study.

BACKGROUND AND PURPOSEA number of studies have examined the relationship between genetic platelet glycoprotein variants and early-onset atherothrombotic disease, particularly acute myocardial infarction. Data on the association of these genetic susceptibility markers with ischemic stroke are more limited, and their role in hemorrhagic stroke has not been previously examined.METHODSWe performed genotype analysis for 5 common diallelic platelet glycoprotein polymorphisms in a population-based study of 78 white women aged <45 years with arterial stroke (36 ischemic cases and 42 hemorrhagic cases) and 346 demographically similar control subjects.RESULTSThe 807T variant of glycoprotein Ia was associated with a 2-fold increased risk of ischemic stroke (age-adjusted odds ratio [OR]=2.24; 95% CI=0.99 to 5.06). The Met(145) allele of glycoprotein Ibalpha was associated with a trend toward an increased risk of ischemic stroke that was more pronounced in the homozygous state (OR=10.36), but the CI is extremely wide because of the small numbers of subjects (95% CI=1.43 to 79.34). Homozygosity for the Ser(843) allele of the glycoprotein IIb was associated with an approximately 5-fold increased risk of ischemic stroke among subgroups of women who carried a diagnosis of hypertension or diabetes (OR=4.51; 95% CI=1.01 to 20.13) or had elevated plasma homocysteine levels (OR=5.94; 95% CI=1.53 to 23.05). The genotype distributions for all 5 platelet glycoprotein polymorphisms were similar among hemorrhagic stroke cases and controls.CONCLUSIONSSeveral inherited platelet glycoprotein variants may be associated with an increased risk of ischemic stroke in young women. These associations seemed to be confined to women with other cardiovascular risk factors. Additional studies involving larger numbers of subjects are needed to confirm these preliminary findings.