Frequency of undetected CYP2D6 hybrid genes in clinical samples: impact on phenotype prediction.
Article Details
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Black JL 3rd, Walker DL, O'Kane DJ, Harmandayan M
Frequency of undetected CYP2D6 hybrid genes in clinical samples: impact on phenotype prediction.
Drug Metab Dispos. 2012 Jan;40(1):111-9. doi: 10.1124/dmd.111.040832. Epub 2011 Oct 17.
- PubMed ID
- 22004686 [ View in PubMed]
- Abstract
Cytochrome P450 2D6 (CYP2D6) is highly polymorphic. CYP2D6-2D7 hybrid genes can be present in samples containing CYP2D6*4 and CYP2D6*10 alleles. CYP2D7-2D6 hybrid genes can be present in samples with duplication signals and in samples with homozygous genotyping results. The frequency of hybrid genes in clinical samples is unknown. We evaluated 1390 samples for undetected hybrid genes by polymerase chain reaction (PCR) amplification, PCR fragment analysis, TaqMan copy number assays, DNA sequencing, and allele-specific primer extension assay. Of 508 CYP2D6*4-containing samples, 109 (21.5%) harbored CYP2D6*68 + *4-like, whereas 9 (1.8%) harbored CYP2D6*4N + *4-like. Of 209 CYP2D6*10-containing samples, 44 (21.1%) were found to have CYP2D6*36 + *10. Of 332 homozygous samples, 4 (1.2%) harbored a single CYP2D7-2D6 hybrid, and of 341 samples with duplication signals, 25 (7.3%) harbored an undetected CYP2D7-2D6 hybrid. Phenotype before and after accurate genotyping was predicted using a method in clinical use. The presence of hybrid genes had no effect on the phenotype prediction of CYP2D6*4- and CYP2D6*10-containing samples. Four of four (100%) homozygous samples containing a CYP2D7-2D6 gene had a change in predicted phenotype, and 23 of 25 (92%) samples with a duplication signal and a CYP2D7-2D6 gene had a change in predicted phenotype. Four novel genes were identified (CYP2D6*13A1 variants 1 and 2, CYP2D6*13G1, and CYP2D6*13G2), and two novel hybrid tandem structures consisting of CYP2D6*13B + *68x2 + *4-like and CYP2D6*13A1 variant 2 + *1xN were observed.
DrugBank Data that Cites this Article
- Pharmaco-genomics
Drug Interacting Gene/Enzyme Allele name Genotypes Defining change(s) Type(s) Description Details Metoprolol Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
ADR Inferred Increased risk of slow heart rate (bradycardia) Details Venlafaxine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, nausea, vomiting and diarrhea Details Codeine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements Details Amitriptyline Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, higher risk for adverse side effects Details Imipramine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, higher risk for adverse side effects Details Dextromethorphan Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements Details Nortriptyline Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, higher risk for adverse side effects Details Tamoxifen Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor response to drug treatment, shorter time to relapse Details Desipramine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, higher risk for adverse side effects Details Clomipramine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, lower dose requirements, higher risk for adverse side effects Details Atomoxetine Cytochrome P450 2D6
Gene symbol: CYP2D6
UniProt: P10635CYP2D6*13 Not Available - CYP2D7/2D6 hybrid gene structure
Effect Inferred Poor drug metabolizer, increased side effects. Details