Letaief Afef*, Benothmane Leila, Charfeddine Bassem, Ennez Hajri Samia, Guider Jridi and Limem Khalifa
Background: Nitric oxide (NO) plays a major role in the regulation of vascular tone associations between NO genotypes. Coronary artery disease (CAD) and other risk factors have been described by many authors. The aim of this study was to investigate the role of endothelial nitric oxide synthase (eNOS) gene intron 4a/b variable number of tandem repeats (VNTR) polymorphism and other risk factors in the developement of CAD in subjects of the Tunisian population.
Method: A total of 274 Tunisian patients with CAD and 162 healthy controls were included in the study. The eNOS gene inton 4a4b variable number of tandem repeats polymorphism was analysed by PCR. The plasma lipid levels and other risk factors were also determined in all subjects.
Results: A significant differences in genotype distribution and allele frequency was observed between patients and controls. Patients with CAD had a frequency of 2.4% for the 4a4a genotype, 63.9% for the 4a4b genotype and 33.7% for the 4b4b genotype. The controls had a frequency of only 6.3% for the 4a4a genotype, 30.4% for the 4a4b genotype and 63.3% for the 4b4b genotype (2=43.75, p=0.000). The CAD patient group showed a significant higer frequency of the 4a allele compared to the controls (0.34 vs. 0.21; 2=15.31, p=0.000). The odds ratio of CAD for 4a vs. 4b allele frequency was statistically significant 1.9 [1.37-2.64] at 95% CI.
The mean serum NO levels in CAD was no significant association between the patients and the control group (p=0.49).
Conclusion: The present study showed a significant and independent association between the eNOS 4a4b gene polymorphism (presence of 4a allele) and CAD but no significant difference between eNOS genotypes and NOx concentrations in CAD patients and controls in the Tunisian population.