Allele and genotype frequencies of CYP2B6 and CYP3A5 in the Japanese population

Masahiro Hiratsuka, Yoh Takekuma, Naomi Endo, Kaori Narahara, Samar Hamdy, Yukinaga Kishikawa, Masaki Matsuura, Yasuyuki Agatsuma, Tomoko Inoue, Michinao Mizugaki

Research output: Contribution to journalArticlepeer-review

119 Citations (Scopus)


Objective: The goal of this study was to determine the frequencies of allelic variants of CYP2B6 and CYP3A5 in the Japanese population. Methods: Genotyping of CYP2B6 (*2, *3, *4, *5, *6, and *7) and CYP3A5 (*2, *3, *4, *5, and *6) was carried out in 265 unrelated Japanese subjects by polymerase chain reaction (PCR), restriction fragment length polymorphism and allele-specific, real-time PCR assays. Results: Allele frequencies for CYP2B6*2, *3, *4, *5, *6, and *7 in 256 Japanese subjects were 0.047, 0, 0.093, 0.011, 0.164, and 0, respectively. Ethnic variation in allele frequencies relative to that in Caucasian subjects was observed for CYP2B6*4 (0.093 vs 0.040), *5 (0.011 vs 0.109), *6 (0.164 vs 0.256), and *7 (0 vs 0.030). Allele frequencies for CYP3A5*2, *3, *4, *5, and *6 in 265 Japanese subjects were 0, 0.740, 0, 0.004, and 0, respectively. The frequency of the CYP3A5*1 allele is 2.8 times higher in Japanese than in Caucasians. Conclusions: Our results contribute to a better understanding of the molecular basis of ethnic differences in drug response, which may help to improve individualization of drug therapy and offer a preliminary basis for more rational use of drugs that are substrates for CYP2B6 and CYP3A5 in the Japanese population.

Original languageEnglish
Pages (from-to)417-421
Number of pages5
JournalEuropean Journal of Clinical Pharmacology
Issue number6
Publication statusPublished - 2002


  • CYP2B6
  • CYP3A5
  • Pharmacogenetics

ASJC Scopus subject areas

  • Pharmacology
  • Pharmacology (medical)


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