Background: The metabolism of many therapeutic drugs depends on the presence and activity of CYP2D6 enzymes. Poor or ultrarapid metabolism may lead to adverse drug effects and lack of therapeutic efficacy. Determining the CYP2D6 gene copy number (GCN) together with SNP genotyping allows predicting the CYP2D6 phenotype and may be beneficial for patients. Efficient TaqMan real-time PCR assays have been developed for this specification but are limited to the Abi Prism system and lack extensive data to demonstrate reliable application for routine purposes.
Materials and methods: We established two TaqMan real-time PCR assays to quantify CYP2D6 GCN on the LightCycler 2.0 platform. With albumin as internal control, one assay targets the exon 9 region of the CYP2D6; the other the intron 6.
Results: In 617 samples there is a 99.4% (exon 9 method) and 95.6% (intron 6 method) correlation compared to standard methods. Analyzing deviant results offer indications for polymorphisms such as CYP2D616 and exon 9 gene conversions.
Conclusion: Established TaqMan real-time PCR assays to determine CYP2D6 GCN on the LightCycler 2.0 are reliable and may be used in the routine. Comparing deviant results, these assays may even allow the screening for rare polymorphism.