Differential quantification of CYP2D6 gene copy number by four different quantitative real-time PCR assays

Anuradha Ramamoorthy, David A. Flockhart, Naoya Hosono, Michiaki Kubo, Yusuke Nakamura, Todd C. Skaar

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

Copy number variations (CNVs) in the CYP2D6 gene contribute to interindividual variation in drug metabolism. As the most common duplicated allele in Asian populations is the nonfunctional CYP2D6*36 allele, the goal of this study was to identify CNV assays that can differentiate between multiple copies of the CYP2D6*36 allele and multiple copies of other CYP2D6 alleles. We determined CYP2D6 gene copy numbers in 32 individuals with known CYP2D6 CNVs from the Coriell Japanese-Chinese panel using four quantitative real-time PCR assays. These assays target different regions of the CYP2D6 gene: 5′-flanking region, intron 2, intron 6, and exon 9 (Ex9). The specific target site of the Ex9 assay was verified by sequencing the PCR amplicon. Three of the CYP2D6 CNV assays (5′-flanking region, intron 2, and intron 6) estimated CYP2D6 copy numbers that were concordant for all 32 individuals. However, the Ex9 assay was concordant in only 10 of 32 samples. The 10 concordant samples did not contain any CYP2D6*36 alleles and the 22 discordant samples contained at least one CYP2D6*36 allele. In addition, the Ex9 assay accurately quantified all of the non-CYP2D6*36 alleles in all samples. Ex9 amplicon sequencing indicated that it targets a region of CYP2D6 exon 9 that undergoes partial gene-conversion in the CYP2D6*36 allele. In conclusion, CYP2D6 Ex9 CNV assay can be used to determine the copy number of non-CYP2D6*36 alleles. Selective amplification of non-CYP2D6*36 sequence by the Ex9 assay should be useful in determining the number of functional copies of CYP2D6 in Asian populations.

Original languageEnglish
Pages (from-to)451-454
Number of pages4
JournalPharmacogenetics and genomics
Volume20
Issue number7
DOIs
Publication statusPublished - 01-07-2010

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Cytochrome P-450 CYP2D6
Gene Dosage
Real-Time Polymerase Chain Reaction
Exons
Alleles
Introns
5' Flanking Region
Gene Conversion

All Science Journal Classification (ASJC) codes

  • Genetics
  • Molecular Biology
  • Molecular Medicine
  • Genetics(clinical)
  • Medicine(all)

Cite this

Ramamoorthy, Anuradha ; Flockhart, David A. ; Hosono, Naoya ; Kubo, Michiaki ; Nakamura, Yusuke ; Skaar, Todd C. / Differential quantification of CYP2D6 gene copy number by four different quantitative real-time PCR assays. In: Pharmacogenetics and genomics. 2010 ; Vol. 20, No. 7. pp. 451-454.
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Differential quantification of CYP2D6 gene copy number by four different quantitative real-time PCR assays. / Ramamoorthy, Anuradha; Flockhart, David A.; Hosono, Naoya; Kubo, Michiaki; Nakamura, Yusuke; Skaar, Todd C.

In: Pharmacogenetics and genomics, Vol. 20, No. 7, 01.07.2010, p. 451-454.

Research output: Contribution to journalArticle

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