Nitric Oxide Synthase 3 Gene Polymorphisms and Their Association with Acute Myocardial Infarction and Chronic Stable Angina: A Case-Control Study from Northern India.

Background: Coronary artery disease (CAD) that encompasses acute myocardial infarction (AMI), chronic stable angina (CSA), and unstable angina (UA) has numerous known risk factors. Genetic predispositions contribute as major risk in the development of CAD and the genes regulating atherosclerosis are important for disease prevention. Nitric oxide synthase 3 (NOS3) gene responsible for nitric oxide (NO) production is of special importance.

Aim: To evaluate the role of three NOS3 polymorphisms (-786C/T, 894G/T, and 4a4b) in patients with CAD, particularly in AMI and CSA and their comparison with healthy controls.

Materials and methods: One hundred patients in each AMI and CSA group and 100 controls were included and were typed for three NOS3 polymorphisms (-786C/T, 894G/T, and 4a4b) by polymerase chain reaction-restriction fragment length polymorphism. Plasma NO metabolites (NOx) were also evaluated.

Results: A significant association of 894G/T polymorphism with AMI in dominant model (P = 0.052) and with CSA in dominant and codominant models was detected (P = 0.008 and P = 0.006, respectively). Plasma NO levels were found to be significantly higher (P < 0.0001) in healthy controls (43.80 ± 6.28) compared to AMI and CSA patients (37.05 ± 6.75 and 38.67 ± 5.61). No significant association of -786C/T and 4a4b polymorphism with AMI and CSA risk under recessive, dominant, and codominant models was detected.

Conclusion: Our study revealed a significant association of 894G/T polymorphism with AMI and independent association of NOx levels with CAD, indicating high risk of CAD in the North Indian population. Our findings will be helpful in identifying the genetic risk factors associated with CAD and better management of the diagnostic as well as therapeutic measures.