Bantu Tanzanians have a decreased capacity to metabolize omeprazole and mephenytoin in relation to their CYP2C19 genotype*

Abstract

Tanzanians have a decreased capacity to metabolize both omeprazole and mephenytoin when their genotype is compared with metabolic capacity and genotype in other previously studied populations. We identified a low frequency of the Asian allele (CYP2C19*3). Although we did not find any new mutations, our results may be consistent with the presence of yet-unidentified mutations of CYP2C19 that causes decreased CYP2C19 activity in the Tanzanian population.

Evaluation of lansoprazole as a probe for assessing cytochrome P450 2C19 activity and genotype–phenotype correlation in childhood

“…Additionally, 19 of these patients were phenotyped with a single oral dose of 20 mg omeprazole at least 1 month after termination of lansoprazole treatment. Peripheral venous blood samples were drawn at 3 h postdose, as previously stated in the literature [27,28]. These patients were selected to include all CYP2C19 genotypes with regard to the CYP2C19*2, CYP2C19*3, and CYP2C19*17 alleles: CYP2C19*1*1 (six patients), *1*17 (seven patients), *1*2 (two patients), *2*2 (two patients), and *17*17 (two patients).…”

Metabolism of citalopram enantiomers in CYP2C19/CYP2D6 phenotyped panels of healthy Swedes

“…Calculations of estimated frequencies of the PM De / PM Me phenotype in different populations are based upon the frequency of PM CYP2C19 of 3% and 20% and CYP2D6 of 7% and 1%, in Europeans and Asians [18], respectively, and analogous calculation in Tanzanians are based upon the frequencies PM CYP2C19 7.5% [19] and PM CYP2D6 7% [20].…”

The high prevalence of the poor and ultrarapid metabolite alleles of CYP2D6, CYP2C9, CYP2C19, CYP3A4, and CYP3A5 in Taiwanese population

“…Both transheterozygous CYP2D6*5/*10 and homozygous CYP2D6*10/*10 represent the IM phenotype. Because of this, in the Taiwanese population it is likely that the IM et al 1996) 0.021 (Nasu et al 1997) 0.011 (Yoon et al 2001) 0.06-0.09 (Scordo et al 2001;Sullivan-Klose et al 1996) 0.005 (Sullivan-Klose et al 1996 CYP2C19*2 0.324 (179) 0.32 (Goldstein et al 1997) 0.23 (Goldstein et al 1997) 0.209 (Herrlin et al 1998) 0.129-0.144 (Goldstein et al 1997;Shimizu et al 2003) 0.25 (Goldstein et al 1997) CYP2C19*3 0.05 (179) 0.055 (Goldstein et al 1997) 0.104 (Goldstein et al 1997) 0.116 (Herrlin et al 1998) 0 (Goldstein et al 1997;Shimizu et al 2003) 0 (Goldstein et al 1997) CYP2D6*5 0.055 (173) 0.072 (Ji et al 2002) 0.003-0.062 (Kubota et al 2000;Fukuda et al 2005) 0.017 …”