Reduced carriership of 4G allele of plasminogen activator inhibitor-1 4G/5G polymorphism in very young survivors of myocardial infarction

There are limited and controversial data regarding the impact of 4G/5G polymorphism of the plasminogen activator inhibitor-1 (PAI-1) gene in the pathogenesis of premature myocardial infarction (MI). We explored whether 4G/5G polymorphism of the PAI-1 gene is associated with the development of MI ≤ 35 years of age. We recruited 201 consecutive patients who had survived their first acute MI ≤ 35 years of age (mean age = 32.2 ± 3.4 years). The control group consisted of 140 healthy individuals matched with cases for age and sex, without a family history of premature coronary heart disease. 4G/5G polymorphism of PAI-1 was tested with polymerase chain reaction and reverse hybridization. 4G allele carriers (4G/4G and 4G/5G genotypes) of PAI-1 were less frequent in patients than in controls (69.6 vs. 83.6%, P = 0.007). 4G carriership of the polymorphism of PAI-1 was associated with lower risk for acute MI (odds ratio 0.45, 95% confidence interval 0.23–0.88, P = 0.02) after adjusting for major cardiovascular risk factors. Patients possessing the 4G allele had higher PAI-1 plasma levels (32.2 ± 25 vs. 22.2 ± 11.3 ng/ml, P = 0.006) but lower lipoprotein(a) levels (10.1 [2.1–29.9] vs. 15.3 [8.2–57.1] mg/dl, P = 0.03) compared to 5G/5G homozygotes. Our data indicate that the 4G allele of the PAI-1 4G/5G polymorphism is less frequent among survivors of MI at very young age compared with matched controls.