Prediction of CYP3A4 enzyme activity using haplotype tag SNPs in African Americans

M. A. Perera*, R. K. Thirumaran, N. J. Cox, S. Hanauer, S. Das, C. Brimer-Cline, V. Lamba, E. G. Schuetz, M. J. Ratain, A. Di Rienzo

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


The CYP3A locus encodes hepatic enzymes that metabolize many clinically used drugs. However, there is marked interindividual variability in enzyme expression and clearance of drugs metabolized by these enzymes. We utilized comparative genomics and computational prediction of transcriptional factor binding sites to evaluate regions within CYP3A that were most likely to contribute to this variation. We then used a haplotype tagging single-nucleotide polymorphisms (htSNPs) approach to evaluate the entire locus with the fewest number of maximally informative SNPs. We investigated the association between these htSNPs and in vivo CYP3A enzyme activity using a single-point IV midazolam clearance assay. We found associations between the midazolam phenotype and age, diagnosis of hypertension and one htSNP (141689) located upstream of CYP3A4. 141689 lies near the xenobiotic responsive enhancer module (XREM) regulatory region of CYP3A4. Cell-based studies show increased transcriptional activation with the minor allele at 141689, in agreement with the in vivo association study findings. This study marks the first systematic evaluation of coding and noncoding variation that may contribute to CYP3A phenotypic variability.

Original languageEnglish (US)
Pages (from-to)49-60
Number of pages12
JournalPharmacogenomics Journal
Issue number1
StatePublished - 2009

ASJC Scopus subject areas

  • Molecular Medicine
  • Genetics
  • Pharmacology


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