The Frequency of Candidate Alleles for CYP2D6 Genotyping in the Japanese Population with an Additional Respect to the − 1584C to G Substitution

The − 1584C/G single nucleotide polymorphism (SNP) in the promoter region of CYP2D6 was suggested to have the potential to influence CYP2D6 activity. In this report, we demonstrated the frequencies of − 1584C to G substitution-related alleles, such as CYP2D6*2, CYP2D6*21, CYP2D6*35 and CYP2D6*41, in the Japanese population. The frequencies of CYP2D6*2, *41 and *21 were 0.102, 0.026 and 0.005, respectively. We also showed a relationship between the SNP and other common alleles, CYP2D6*4, *5, *10, *14 and *18. Interestingly, the SNP was detected in all three subjects carrying CYP2D6*14. This finding suggests the − 1584G is included in the CYP2D6*14 allele, which is a null-allele characteristic to the Japanese population. This report presents practical information on CYP2D6 alleles that should be considered in the pharmacokinetic study of CYP2D6 substrates in the Japanese population.