Abstract

PREVALENCE OF CYP2D6 PHENOTYPES IN A YEMENI POPULATION

AM Othman, Hussien O. Kadi Anes A. M. Thabit

Abstract

Due to lack of information on existence and prevalence of CYP2D6 genetic polymorphism in Yemeni population, this study was undertaken to reveal such information in Yemeni males. 70 healthy unrelated Yemeni males participated voluntarily as subjects in this study. They were categorized into two groups including 50 Arabs in one group and 20 Blacks in the other group. Each subject swallowed a standard dose (30 mg) of dextromethorphan (DM; the probe drug of CYP2D6) and slept overnight. The metabolic ratio of the drug to its major metabolite (dextrorphan; DOP) for each subject was determined by HPLC analysis of his urine sample collected 8 hours post-dosing. CYP2D6 phenotyping depended on the antimode ranges, of log metabolic ratio, that separate the phenotypes from each other. These antimodes were determined from the probit plot of log metabolic ratio of subjects in each group. Each subject was then phenotyped as either ultrarapid , extensive (normal), intermediate and poor metabolizer according to the value of his log metabolic ratio. The prevalence of CYP2D6 phenotype in each group was then calculated. It was found that CYP2D6 poor metabolizer phenotype in the Arab and Black subjects were 4% and 10 %, respectively, while the ultrarapid metabolizer phenotype was observed only in black subjects (20 %). These findings reveal the existence of CYP2D6 genetic polymorphism in both Arab and Black Yemeni males . However, pheno/genotype correlation remains to be established.

Keywords: CYP2D6, Yemeni , phenotypes , dextromethorphan, metabolic ratio.