Polymorphisms of the NOS3 gene and risk of myocardial infarction in the Tunisian population.

Controversial results regarding the association of eNOS gene (NOS3) polymorphisms with myocardial infarction (MI) have been reported. This study investigated the relationship of the -786T>C (rs2070744), 894G>T (rs1799983) and 4a4b polymorphisms of the NOS3 gene with the presence of MI in the Tunisian population. In addition, we also examined the association of NOS3 gene haplotypes with MI in Tunisian subjects. A total of 303 patients with MI and 225 controls were included in the study. The 894G>T and -786T>C single nucleotide polymorphisms were analyzed by PCR-RFLP, and 4a4b polymorphism just for PCR. There was significant linkage disequilibrium between the three NOS3 polymorphisms (p<0.0001). The genotype distribution and allele frequency of NOS3 4a4b, but not -786T>C and 894G>T, polymorphism was significantly different between MI patients and controls. The univariate logistic regression analysis showed a significant association of the 4a4b polymorphism and MI according to co-dominant, dominant and recessive models (co-dominant model OR: 4.38, 95%CI: 1.24-15.41; p=0.021, dominant model OR: 1.66, 95%CI: 1.14-2.42); p=0.007, and recessive model OR: 3.85, 95%CI: 1.10-13.47; p=0.035). The multivariate analysis, adjusted for traditional cardiovascular risk factors, revealed that the NOS3 4a4a genotype was an independent predisposing factor to MI, according to the models considered. In addition, a haplotype 7 (C-T-4a), (OR=12.05, p=0.010) was a risk factor of MI after controlling for classical risk factors. These finding suggest that the 4a4b polymorphism of the NOS3 gene was associated with MI in Tunisian patients.