PURPOSE: although CYP2D6*36 was thought to be one of the alleles causing the poor metabolizer phenotype, several in vitro studies clarified that the enzyme produced by CYP2D6*36 showed enzymatic activities. However, the effects of CYP2D6*36 in tandem with CYP2D6*10 on the in vivo CYP2D6 activity have been unclear. In this study, we investigated in vivo metabolic capacities of CYP2D6 among the subjects carrying different numbers of CYP2D6*36 in tandem with CYP2D6*10. METHODS: we measured the metabolic ratio (MR) of dextromethorphan in 98 subjects. We determined the CYP2D6 genotype of these subjects, including allelic copy number of CYP2D6*10 and CYP2D6*36 by direct sequencing, TaqMan assay, and real-time Invader assay. RESULTS: single copies of CYP2D6*10 and tandem duplication of CYP2D6*36-*10 alleles were found at frequencies of 8.7 and 32.7%, respectively. Median dextromethorphan MRs of the subjects carrying CYP2D6*10 and CYP2D6*36-*10 were not significantly different (P = 0.24). CONCLUSIONS: CYP2D6*36 in tandem with CYP2D6*10 plays a minor role in interindividual variation of dextromethorphan metabolism in vivo.
PURPOSE: although CYP2D6*36 was thought to be one of the alleles causing the poor metabolizer phenotype, several in vitro studies clarified that the enzyme produced by CYP2D6*36 showed enzymatic activities. However, the effects of CYP2D6*36 in tandem with CYP2D6*10 on the in vivo CYP2D6 activity have been unclear. In this study, we investigated in vivo metabolic capacities of CYP2D6 among the subjects carrying different numbers of CYP2D6*36 in tandem with CYP2D6*10. METHODS: we measured the metabolic ratio (MR) of dextromethorphan in 98 subjects. We determined the CYP2D6 genotype of these subjects, including allelic copy number of CYP2D6*10 and CYP2D6*36 by direct sequencing, TaqMan assay, and real-time Invader assay. RESULTS: single copies of CYP2D6*10 and tandem duplication of CYP2D6*36-*10 alleles were found at frequencies of 8.7 and 32.7%, respectively. Median dextromethorphan MRs of the subjects carrying CYP2D6*10 and CYP2D6*36-*10 were not significantly different (P = 0.24). CONCLUSIONS:CYP2D6*36 in tandem with CYP2D6*10 plays a minor role in interindividual variation of dextromethorphan metabolism in vivo.
Authors: Wing Chan; Man S Li; Senthil K Sundaram; Brian Tomlinson; Pik Y Cheung; Chi H Tzang Journal: J Clin Lab Anal Date: 2018-08-01 Impact factor: 2.352
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