CYP2D6 Genotyping for Functional-Gene Dosage Analysis

of themost important drug-metabolizing enzymes, has been reported to possess variation in the encoding CYP2D6 gene (cytochrome P450, family 2, subfamily D, polypeptide 6) that affects enzymatic activity. For the pharmacogenetic study of CYP2D6, accurate mea-surement of the dosage of the functional gene is essen-tial; however, current genotyping techniques are insuf-ficient because of their inability to provide the exact copy number of functional CYP2D6 genes. METHODS: We developed 3 quantitative real-time PC