Association of Variable Number of Tandem Repeats in Endothelial Nitric Oxide Synthase Gene with Coronary Artery Disease

Endo-derived nitric oxide (no) is synthesized from l-arginine by endothelium nitric oxide synthase (enos). since reducedno synthesis has been implicated in the development of coronary atherosclerosis; we hypothesized that polymorphisms ofnos gene might be associated with increased susceptibility to this disorder and coronary artery disease (cad). we studiedthe 27 base pair tandem repeat polymorphism in intron4 of the endothelial nitric oxide synthase (enos) gene in 141 unrelatedcad patients with positive coronary angiograms in shahid rajaee heart hospital and 159 age matched control subjectswithout a history of symptomatic cad. the study protocol was approved by the iran university of medical sciences ethics committee. the enos gene intron4a/b vntr polymorphism was analyzed by polymerase chain reaction. theplasma lipids levels and other risk factors were also determined. the genotype frequencies for enos4b/b, enos4a/b andenos4a/a were 68.8, 29.1 and 2.1% in cad subjects, and 81, 18.4 and 0.6 % in control subjects, respectively. the genotypefrequencies differed significantly between the two groups (÷²= 6.38 p= 0.041). the frequency of the allele was 16.7%in cad subjects and 9.8% in control subjects and was significantly higher in the patients (÷²= 6.18 p= 0.013, odds ratio=1.84). plasma lipids, except hdl-c were also remarkablely increased in cad group.