Potential reasons for this finding include the following: the ADRB2 rs1042714 polymorphism results in the substitution of Glu for Gln at codon 27, and the “gain-of-function” of the receptor conferred by the Glu27 allele could cause target tissues to be overexposed to catecholamine, thus accelerating the development of CAD and exacerbating heart dysfunction (Barbato et al., 2007). This evidence concerns the gene ADRB2 and coronary artery disorder.