2001 年 16 巻 2 号 p. 69-74
Approximately 1% of Orientals and 7 to 10% of Caucasians lack the activity of cytochrome P450 (CYP) 2D6, and these individuals are known as poor metabolizers (PM). On the other hand, approximately 4% of Caucasians are PM of CYP2C19, while its frequencies are 18 to 23% in Orientals. These differences in the frequencies of PM seen in the different ethnic populations are mainly due to the differences in the distribution frequency of variously defective alleles of CYP2D6 and 2C19. Recent progress in molecular biology of CYPs has enabled the mechanism of CYP polymorphism to be elucidated and the polymerase chain reaction was developed for its genotyping. Our previous studies showed that the frequencies of CYP2C19*2, *3, CYP2D6*2, *5, *10, *14, and CYP2C9*3 among the Japanese subjects were 28.7, 13.2, 12.9, 6.2, 38.6, 2.2 and 2.1%, respectively. In this review, we compared the frequencies of these mutant alleles of CYPs seen in the Japanese population with those reported previously for other ethnic populations.