The cases were hospitalized patients from two medical centers in Beijing and Harbin respectively. Venous blood was collected by standard vein puncture in fasting condition.

In our study, the CAD was defined by one of the following criteria: (1) based on World Health Organization criteria in terms of elevations of cardiac enzymes, electrocardiography (ECG) and clinical symptoms (angina, chest pressure, or shortness of breath); (2) angiographic evidence of more than 50% stenosis in one or more major coronary arteries; (3) previous history of PCI (percutaneous coronary intervention) or CABG (coronary artery bypass graft). The controls were selected from the two medical centers meeting the following criteria: (1) with no family history for CAD; (2) no clinical symptoms for CAD; (3) resting ECG showed normal results. The subjects with two or more risk factors of CAD (age>45 for man and >55 for woman, hypertension, diabetes, overweight, hyperlipidemia) were subjected to treadmill stress test and selected as controls if their ECG were normal without clinical symptoms. Those with history of cardiomyopathy, valvular disease, peripheral vascular disease, stroke, severe hepatic and kidney deficiency were excluded in our study.

Venous blood was collected by standard vein puncture in fasting condition. Four single-nucleotide polymorphisms (SNPs) (rs7586970, rs6434222, rs10153820 and rs8176528) were detected with polymerase chain reaction-direct sequencing method. And the genotypes of these SNPs were determined in both CAD patients and non-CAD controls.

Inclusion Criteria:

The coronary artery disease was defined by one of the following criteria-(1) based on World Health Organization criteria in terms of elevations of cardiac enzymes, electrocardiography (ECG) and clinical symptoms (angina, chest pressure, or shortness of breath); (2) angiographic evidence of more than 50% stenosis in one or more major coronary arteries; (3) previous history of PCI (percutaneous coronary intervention) or CABG (coronary artery bypass graft).

The controls were selected from the two medical centers meeting the following criteria: (1) with no family history for CAD; (2) no clinical symptoms for CAD; (3) resting ECG showed normal results. The subjects with two or more risk factors of CAD (age>45 for man and >55 for woman, hypertension, diabetes, overweight, hyperlipidemia) were subjected to treadmill stress test and selected as controls if their ECG were normal without clinical symptoms.

Exclusion Criteria:

• Those with history of cardiomyopathy, valvular disease, peripheral vascular disease, stroke, severe hepatic and kidney deficiency were excluded in our study.

The cases were all hospitalized patients recruited from two medical centers in Beijing and Harbin.

The participants with two or more risk factors of CAD (age>45 for man and >55 for woman, hypertension, diabetes, overweight, hyperlipidemia) were subjected to treadmill stress test and selected as controls if their ECG were normal without clinical symptoms.