Frequency of CYP2C19*2 Allele in Patients with Acute Coronary Syndrome: A Cross-sectional Study from Central Kerala, India

Abstract

Introduction: Ischaemic Heart Diseases (IHD) are increasing at an alarming rate globally. Pharmacotherapy, the mainstay of management of IHD, has Dual Antiplatelet Therapy (DAPT) at its crux. DAPT, comprising of clopidogrel and aspirin, is used often for 12 months in medically managed Acute Coronary Syndrome (ACS). Clopidogrel being a prodrug, needs to be activated after ingestion, mainly by Cytochrome family of enzymes, for the desired pharmacological effects. Abnormal enzymes that convert clopidogrel to its active form can reduce the effectiveness of the drug. Therefore, Single Nucleotide Polymorphisms (SNPs) of the enzymes involved, would predispose the patient to therapy failure and recurrence of the illness. This study aims at identifying the presence of a genetic variant associated with clopidogrel responsiveness in patients with ACS. Aim: To estimate the frequency of CYP2C19*2 allele in patients with ACS presenting to Government Medical College, Thrissur, Kerala, India. Materials and Methods: Present study was a cross-sectional study done among 60 patients who presented to Government Medical College, Thrissur with ACS, between June 2018 to June 2019. Having obtained informed consent from the participants blood samples were collected in Ethylene diamine tetra-acetic Acid (EDTA) tubes. Samples were used to look for presence of CYP2C19*2 allele by Polymerase Chain Reaction-Restriction Fragment Length Polymorphism (PCR-RFLP). Results: Out of 60 patients 38 were males and 22 were females. Most common age group was 61-65 years. The frequency of CYP2C19*2 allele was 41% in the study population and the variant genotype (AA/AG) was present in 62%. Conclusion: The variant genotype was found to be present in a high frequency in the study population implying the high risk for therapy failure in the study population. This asserts the need to probe the matter further, as the gene is also implicated in the metabolism of several other drugs. The introduction of pharmacogenomic testing prior to initiation of therapy may be therefore recommended for better treatment outcome. However, to validate the same, further studies with larger sample size may be necessary.