The frequency of candidate alleles for CYP2D6 genotyping in the Japanese population with an additional respect to the -1584C to G substitution.

Summary: 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.