AimTo investigate a potential association of the gene polymorphisms of endodermis nitricoxide synthase(eNOS) and N5, N10 methylene tetrahydrofolate reductase (MTHFR) gene with premature coronary artery disease (PCAD).MethodsThe polymorphisms of gene eNOS and MTHFR were measured by polymerase chain reaction and restriction fragment length polymorphism analysis(PCR-RFLP) in 131 patients with PCAD (PCAD group)and 131 non-coronary heart disease patients (control group), who were matched in age and sex.ResultsThe frequencies of eNOS G894T gene polymorphism (χ²=2.072, p=0.355) and its T allele (χ²=0.727, p=0.394) in PCAD group were not significantly different from those in control group.The frequencies of MTHFR C677T gene polymorphism T allele were significantly higher in PCAD group than those in control group(χ²=16.339, p=0.000).The frequencies of the three genotypes (CC, CT and TT) were significantly different between the two groups(χ²=14.290, p=0.001).Logistic regression analysis indicated that MTHFR 677C/T TT genotype was an independent risk factor in PCAD(p<0.05).ConclusionThe eNOS G894T polymorphism may have no association with the pathogenesis of PCAD in Han patients of Swnan region; the TT genotype of the MTHFR C677T gene may increase the risk of PCAD.The genetic polymorphism of MTHFR gene promoter is associated with the susceptibility to PCAD in Suwan Han nationality.