Available online at www.scholarsresearchlibrary.com Scholars Research Library Annals of Biological Research, 2010, 1 (4) : 152-157 (http://scholarsresearchlibrary.com/archive.html) ISSN 0976-1233 CODEN (USA): ABRNBW 152 Scholars Research Library Sequence variation in eNOS (Glu298Asp) gene and its impact on coronary artery disease: North Indian Study Rajneesh Tripathi, Vandana Arya, P. K.Singh* and Sarita Agarwal Department of Genetics, *Department of Anesthesiology Sanjay Gandhi Postgraduate Institute of Medical Sciences, SGPGIMS, Lucknow, India _____________________________________________________________________________ ABSTRACT Endothelium-derived nitric oxide (NO) synthesized from L-arginine by endothelial nitric oxide synthase (eNOS) encoded by the NOS3 gene. Polymerase chain reaction restriction fragment length polymorphism (PCR-RFLP) analysis of NOS3 identifies G to T substitution at 984 position of exon 7 which changes Glu to Asp amino acid at codon 298. We have done case- control association study to investigate the relationship between Glu298Asp variant and coronary artery disease (CAD) of North Indian origin. The study consists of 199 unrelated patients with positive history of coronary artery disease and 153 unrelated healthy individuals without having history of CAD. Though we did not find any significant association of eNOS gene polymorphism with coronary artery disease (p=0.077), a stepwise increase in frequency of T allele of eNOS gene with the severity in terms of number of vessels involved was observed (T allele in one, two and three vessel; 10.2%, 14.5% and 16.4% respectively). Presence of diabetes, hypertension, smoking, elevated level of triglycerides and reduced level of HDL cholesterol were found as significant predictors of coronary artery disease on multivariable logistic regression analysis. A larger sample size study is needed to evaluate the association of eNOS polymorphism and CAD. Key words Coronary artery disease, eNOS, Glu298Asp polymorphism __________________________________________________________________________ INTRODUCTION Nitic oxide (NO) a powerful short-lived vasoactive substance is constitutively produced from L- arginine by the enzyme eNOS (Moncada et al., 1993). It plays a key role in the relaxation of vascular smooth muscle, inhibits adhesion of platelets and leukocytes to the endothelium and reduces vascular smooth muscle cells migration and proliferation. Moreover, it has been shown that eNOS inhibition accelerates atherosclerosis in animal models and that abnormalities in the endothelial NO pathways are associated with atherosclerosis in humans (Cayatte et al., 1994; Ludmer et al., 1986). Several polymorphisms have been identified in the eNOS gene. Among