ABSTRACT
Coronary artery disease (CAD)is a major cause of death and disability worldwide, and consumes a considerable amount of medical resources every year.Clopidogrel is a first-line antiplate-let therapy for CHD, butit is associated with substantial variability in PK and pharmacodynamics re-sponse. To date, gene variants explain only a smallproportion of the variability.The study aimed to identify new genetic loci-modifying antiplatelet response to clopidogrel in Chinese patients with CAD by a systematic analysis combining antiplatelet effects and PK, and further to investigate the PON1 gene promoter DNA methylation and genetic variations possibly influencing clinical outcomes in pa-tients undergoing PCI. We identified novel variants in two transporter genes (SLC14A2rs12456693, ATP-binding cassette [ABC]A1 rs2487032) and in N6AMT1 (rs2254638) associated with P2Y12 reac-tion unit (PRU) and plasma active metabolite (H4) concentration. These new variants dramatically im-proved the predictability of PRU variability to 37.7％. The associations between these loci and PK pa-rameters of clopidogrel and H4 were observed in additional patients, and its function on the activation of clopidogrel was validated in liver S9 fractions (P<0.05). Rs2254638 was further identified to exert a marginal risk effect formajor adverse cardiac events in an independent cohort.Multivariate logistic regression analysis indicated that PON1methylation level at CpG site-161 (OR=0.95; 95％ CI=0.92–0.98;P<0.01)and the use of angiotensin converting enzyme inhibitors(OR=0.48;95％ CI=0.26–0.89;P<0.01) were associated with decreased risk of bleeding events. In conclusion, new genetic variants were systematically identified as risk factors for the reduced efficacy of clopidogrel treatment.The ab-normal expression of DNA methylation-regulating key genes in the pharmacokinetic and pharmacody-namics pathways of clopidogrel and aspirin may modify clinical outcomes in dual antiplatelet-treated pa-tients undergoing PCI.