The endothelial nitric oxide synthase gene (eNOS), a strong candidate at the Chr 5 locus, and plasma levels of arginine, the substrate for NO production, are correlated with atherosclerosis and are regulated by a locus on Chr 7 that contains the gene Nosip1. Further understanding how NO metabolism is regulated may identify novel targets for atherosclerosis treatment. This evidence concerns the gene NOS3 and atherosclerosis.