The Prevalence of CYP2C19 Polymorphism in Patients with Symptomatic Intracranial Atherosclerosis

Abstract

Introduction: Clopidogrel and aspirin were proved to have benefit in symptomatic intracranial stenosis. CYP2C19 polymorphism (CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17 alleles) affects efficacy of clopidogrel. Epidemiologic study of CYP2C19 polymorphism has been conducted in Thai population. There was no data showed the frequency of allelic variants of CYP2C19 in Thai symptomatic intracranial stenosis patients. The aim of this study was to determine the prevalence of CYP2C19 polymorphism in symptomatic intracranial stenosis patients. Methods: The study group included 100 Thai symptomatic intracranial stenosis patients. Genotyping of CYP2C19 alleles (CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17 alleles) was carried out by real-time polymerase chain reaction (rt-PCR) technique. Results: The allele frequency of CYP2C19*1, CYP2C19*2, CYP2C19*3, and CYP2C19*17 were 70.5%, 26%, 2.5%, and 1%, respectively. The result showed that 53% of symptomatic intracranial stenosis patients are normal metabolizers, while intermediate and poor metabolizer were 36 and 10 percent, respectively. Conclusion: Almost one-half of Thai symptomatic intracranial stenosis patients were intermediate or poor metabolizers. Usage of combination of aspirin and clopidogrel might not be effective in this group of patients.