CYP3A4 and CYP3A5genotyping by Pyrosequencing

Abstract

BackgroundHuman cytochrome P450 3A enzymes, particularly CYP3A4 and CYP3A5, play an important role in drug metabolism. CYP3A expression exhibits substantial interindividual variation, much of which may result from genetic variation. This study describes Pyrosequencing assays for key SNPs in CYP3A4 (CYP3A4*1B, CYP3A4*2, and CYP3A4*3) and CYP3A5 (CYP3A5*3C and CYP3A5*6).MethodsGenotyping of 95 healthy European and 95 healthy African volunteers was performed using Pyrosequencing. Linkage disequilibrium, haplotype inference, Hardy-Weinberg equilibrium, and tag SNPs were also determined for these samples.ResultsCYP3A4*1B allele frequencies were 4% in Europeans and 82% in Africans. The CYP3A4*2 allele was found in neither population sample. CYP3A4*3 had an allele frequency of 2% in Europeans and 0% in Africans. The frequency of CYP3A5*3C was 94% in Europeans and 12% in Africans. No CYP3A5*6 variants were found in the European samples, but this allele had a frequency of 16% in the African samples. Allele frequencies and haplotypes show interethnic variation, highlighting the need to analyze clinically relevant SNPs and haplotypes in a variety of ethnic groups.ConclusionPyrosequencing is a versatile technique that could improve the efficiency of SNP analysis for pharmacogenomic research with the ultimate goal of pre-screening patients for individual therapy selection.

Pharmacogenetic study in Hodgkin lymphomas reveals the impact of UGT1A1 polymorphisms on patient prognosis

“…Allelic distributions of these genes were similar to those previously reported in Western populations. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23] We made the hypothesis that relevant polymorphisms previously reported for other studies in humans treated with chemotherapy could have an impact on the outcome of patients treated for Hodgkin lymphoma. This study has several limitations.…”

Genetic variation at the tumour virus B locus in commercial and laboratory chicken populations assessed by a medium-throughput or a high-throughput assay

“…The pyrosequencing analysis protocol is similar to reported procedures (Zackrisson & Lindblom, 2003;Garsa et al, 2005). Briefly, the single-stranded DNA template was prepared in a 96-well PCR plate with 20 ml PCR applicon, 60 ml binding reaction solution consisting of 3 ml streptavidin Sepharose beads (Amersham Biosciences AB, Uppsala, Sweden), 40 ml binding buffer (10 mM Tris ÁHCl, pH 7.6, 2 M NaCl, 1 mM etnylenediamine tetraacetic acid, 0.1% Tween 20), and 17 ml ddH 2 O each.…”

Analysis of CYP3A4 genetic polymorphisms in Han Chinese

“…We further compared allele frequencies of CYP3A4 among different ethnic groups and demonstrated remarkable interpopulation difference, with regard to allelic distribution (Table 3). CYP3A4*1B, the most frequent allele in Africans (82%), 12 has significantly lower incidence in Caucasians (4%) 12,52 and is near extinction in Asians. 53,54 This allele is present in about 0.5% of Han Chinese population, a higher incidence than in Malays 18 and Japanese.…”

“…The most prevalent variant is CYP3A4*1B, with allele frequency ranging from 0B4% in Asians and Europeans to 82% in Africans. 11,12 The elimination of CYP3A4*1B in non-African populations has been suggested to be a consequence of selective advantage. 13 This variant might moderately enhance CYP3A4 gene expression, by virtue of reduced binding ability of a transcriptional repressor.…”