PCSK9 and coronary artery disorder: Recently, proprotein convertase subtilisin/kexin type 9 (PCSK9) is considered as a major risk factor for CAD, which plays an important role in cholesterol metabolism by increasing the degradation of hepatic low density lipoprotein cholesterol receptors (LDLR), thereby resulting in increasing circulating low density lipoprotein cholesterol (LDL-C) levels [6, 7].