Endothelial Nitric Oxide Synthase Intron 4 Polymorphism Is a Marker for Coronary Artery Disease in African-American and Caucasian Men

We investigated the association of the intron 4 polymorphism of the endothelial nitric oxide synthase (eNOS) gene with coronary artery disease (CAD). Genetic alterations in the gene encoding for eNOS could contribute to the development and progression of CAD. We genotyped for the eNOS intron 4 polymorphism in 194 subjects undergoing coronary angiography. Genotyping was performed with polymerase chain reaction-restriction fragment length polymorphism for the variable number of tandem repeats in intron 4. Coronary artery disease (CAD) was assessed by quantitative coronary angiography, and endothelial function was measured by brachial ultrasonography. We performed logistic regression analysis for the effect of eNOS intron 4 polymorphism and other coronary risk factors on multi-vessel CAD and endothelial function. The 4a-allele frequency in African Americans was 0.31, while the 4a-allele frequency in Caucasians was 0.15 (P