Insertion/insertion genotype of α 2B-adrenergic receptor gene polymorphism is associated with silent myocardial ischemia in patients with type 2 diabetes mellitus

Abstract

Objectives We investigated whether α 2-adrenergic receptor (AR) polymorphisms (α 2A-AR, α 2B-AR and α 2C-AR gene) affected silent myocardial ischemia (SMI) in patients with type 2 diabetes mellitus (T2DM). Design and methods Genetic polymorphisms were determined in 321 patients with T2DM and coronary artery disease (CAD). Among them, 129 patients experienced transient asymptomatic ST-depression during 24-hour ambulatory electrocardiogram (SMI group), and the remaining 192 patients who had ambulatory electrocardiogram-symptom matching angina were categorized as angina group. Results The genotype distribution and allele frequencies of α 2B-AR gene polymorphism (insertion [I]/deletion[D]) exhibited significant difference between SMI group and angina group (both P < 0.05), with genotype II (34.9%) being higher in SMI group than in angina group (19.8%)(P < 0.01). Multivariable logistic regression analysis revealed that duration of diabetes and genotype II of α 2B-AR gene polymorphism were independently associated with SMI. Conclusions Homozygote for I allele of α 2B-AR gene polymorphism is associated with SMI in T2DM patients with CAD.