In this study, we established useful and reliable methods for the direct detection of the variants of CYP3A5 gene by polymerase chain reaction (PCR) and Dde I restriction analysis. The frequency of CYP3A5 related SNPs in 200 healthy Japanese male subjects was determined. The homozygous wild-type (*1/*1) frequency was 7.0% (14/200), the heterozygous (*1/*3) frequency was 32.5% (65/200) and the homozygous mutant-type (*3/*3) frequency was 60.5% (121/200). The *6 allele was not detected in any of the Japanese individuals. This result suggests that an estimated 40% of the Japanese express relatively high levels of metabolically active CYP3A5 protein. The proposed detection assays are useful for screening the CYP3A5 related SNPs in pharmacogenetic research.
aClinical Evaluation of Medicines and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, 1–6 Yamadaoka, Suita, Osaka 565-0871, Japan, bThe organization for Pharmaceutical Safety and Research, Tokyo, Japan andcDepartment of Pharmacology, University of Toronto Faculty of Medicine, Toronto, Ontario, Canada M5S 1A8
Correspondence to Junichi Azuma, Clinical Evaluation of Medicines and Therapeutics, Graduate School of Pharmaceutical Sciences, Osaka University, 1-6 Yamadaoka, Suita, Osaka 565-0871, Japan. Tel: +81-6-6879-8258; fax: +81-6-6879-8259; e-mail: firstname.lastname@example.org
Received 15 August 2001
Accepted 11 January 2002