Frequency of cytochrome P4502C9 mutant alleles in a Korean population

Aims To determine the frequencies of CYP2C9 variants in the Korean population and compare them with the frequencies in other ethnic populations. Methods Genotyping of CYP2C9(star)2 and CYPC9 star3 allelic variants was carried out in 574 Korean subjects by PCR and restriction fragment length pattern analysis. Results Thirteen of 574 subjects (2.3%) were heterozygous for CYP2C9 star3 (Ile(359)Leu), but no subjects with a CYP2C9 star2 allele or homozygous for CYP2C9 star3 were identified. The allele frequency of CYP2C9 star3 in Korean subjects (0.0113, 95% CI 0.0066-0.0193) was similar to that of-other East Asian populations, but was considerably lower than that of Caucasian populations. Conclusions CYP2C9 star3 seems to be an allelic variant related to the functional polymorphism of CYP2C9. but this variant is rarely seen among Koreans compared with Caucasians. Routine genotyping of the CYP2C9C star2 allele is considered to be unnecessary in Korean and East Asians, because this allele appears to be extremely rare or absent in these populations.