IntroductionThe study of polymorphisms and their relationship with diseases is very important for risk assessment. The aim of this study was to determine the relationship between early risk of coronary artery disease(CAD) with renin-angiotensin(RAS) genes and endothelial nitric oxide synthase(eNOS) in a sample of the Iranian population.Methods & materialsIn this cross-sectional study, 63 patients with premature CAD and 72 healthy samples were enrolled. Polymorphism of the promotor region of eNOS- and ACE-I/D (Angiotensin Converting Enzyme-I/D) polymorphism was evaluated. Polymerase chain reaction (PCR) test and PCR-RFLP (Restriction Fragment Length Polymorphism) was performed for ACE and eNOS-786 gene, respectively.ResultsThe frequency of deletion(D) for the ACE gene was significantly higher in patients(96% versus 61%; P < 0.001). Conversely, the number of defective C alleles for the eNOS gene was similar in both groups (p > 0.9).ConclusionACE polymorphism seems to be an independent risk factor for premature CAD.