NOS3 and obesity due to melanocortin 4 receptor deficiency: Except well-known traditional risk factors such as dyslipidemia, high blood pressure, diabetes, obesity, smoking, physical inactivity and age, recently, genetic factors including angiotensin-converting enzyme (ACE) gene3, serotonin transporter (SLC6A4) gene4, endothelial nitric oxide synthase (eNOS) gene5 have been reported to link with the risk of MI.