The clinical effects of CYP2C19 *2 allele frequency on Palestinian patients receiving clopidogrel after percutaneous coronary intervention

BackgroundCYP2C19 loss-of-function polymorphic alleles (*2 and *3) have been documented to impair clopidogrel metabolism, and represent a risk factor for major adverse cardiac events. CYP2C19 polymorphism exhibits marked ethnic heterogeneity. Objective To determine the prevalence of CYP2C19 *2 and *3 alleles in a cohort of Palestinian patients managed with percutaneous coronary intervention and dual antiplatelet therapy, and to determine their role in causing major adverse cardiac events. Setting The blood samples were collected at the European Gaza Hospital, and the molecular techniques performed at the molecular genetics laboratory of the Islamic university of Gaza. Method The frequency of CYP2C19 *2 and *3 alleles was determined in 110 patients managed with percutaneous coronary intervention and clopidogrel. Genotyping was performed by PCR–RFLP. Personal and clinical data was obtained from patient record and 6-month follow-up for major adverse cardiac events. Main outcome measureCYP2C19 genotype, personal and clinical data and incidence of major adverse cardiac events. Results The frequency of CYP2C19 *1, *2 and *3 alleles was 82.3%, 15.5% and 2.3% respectively. Genotyping analysis showed that, 67.3% were homozygotes for CYP2C19 *1, 27.3% were *1/*2, 2.7% with *1/*3 genotype, 1.8% were *2/*3 and 0.9% were *2/*2. These frequencies were consistent with those of Caucasian populations. According to this study the poor metabolizers phenotype frequency was 2.7%, which is in the same range reported in Caucasians (2–5%) and lower than Oriental populations 13–23%. A strong significant relation was found between major adverse cardiac events and carrying the variant allele CYP2C19 *2 (P = 0.001). On the other hand, there was no significant relation between major adverse cardiac events and carrying the variant allele CYP2C19 *3 (P = 0.324). Conclusion The CYP2C19 *2 allele is relatively common in our population, and its associated reduced metabolic activity deserves attention as it leads to an increased incidence of major adverse cardiac events in the follow-up of patients receiving clopidogrel.