Aim: Cytochrome P450 2C9 (CYP2C9) is a polymorphic enzyme responsible for the metabolism of a large number of clinically important drugs. Individuals with mutant enzymes may risk serious side effects under routine therapy with certain drugs metabolized by CYP2C9. In order to facilitate the detection of the known SNPs of CYP2C9, an allele-specific oligonucleotide (ASO) based microarray was made.
Methods: An oligonucleotide microarray was made to facilitate the SNP (single nucleotide polymorphism) screening and was applied for the detection of CYP2C9 polymorphism in 62 high blood pressure (HBP) patients who received Irbesartan for treatment. Part of the genotyping results was confirmed by direct sequencing. And the relation between CYP2C9 polymorphism and therapeutic outcome of Irbesartan was statistically analyzed.
Results: Heterozygous alleles of CYP2C9*1/*3 were found in 7 out of 62 subjects. No mutant alleles of CYP2C9*2, *4 and *5 and no homozygous mutant alleles were detected. The 7 heterozygous CYP2C9*1/*3 and 13 random wild type DNA samples were subjected to direct sequencing with purified PCR products and same genotyping results were obtained with the 20 DNA samples. There was no significant difference in the odds of effectiveness of Irbesartan between the wild type (normal) group and CYP2C9*1/*3 (mutant) group (P>0.05).
Conclusion: The oligonucleotide microarray made in this study is a reliable assay for detecting the CYP2C9 known alleles and the heterozygous CYP2C9*1/*3 has no significant effects on the therapeutic outcome of Irbesartan.