High metabolic N-oxidation of voriconazole in a patient with refractory aspergillosis and CYP2C19*17/*17 genotype

MGB Block ARMS Real-Time PCR for Diagnosis of CYP2C19 Mutation in a Chinese Population

Background:

CYP2C19 is an important genetic factor modulating clopidogrel dose requirement.

Objective:

Therefore, a simple and economic genotyping method for predicting the clopidogrel dose of patients would be useful in clinical applications.

Methods:

In this study, the MGB blocker ARMS real-time PCR contained two forward primers, two MGB blockers and a common reverse primer have been used for CYP2C19*2, *3 and *17 substitutions.

Results:

Results showed that heterozygotes and homozygotes of CYP2C19*2, *3 and *17 could be distinguished by the MGB blocker ARMS real-time PCR successfully. In the Chinese population, patients with allele frequencies of CYP2C19*2, *3, and *17 are 18.43%, 3.03% and 0.76%, respectively.

Conclusion:

This study indicates that the MGB blocker ARMS real-time PCR will be a simple, economical method for the rapid detection of SNPs in CYP2C19.

High-Resolution Melting Assay for Genotyping Variants of the CYP2C19 Enzyme and Predicting Voriconazole Effectiveness

Voriconazole is a triazole antifungal agent recommended as primary treatment for invasive aspergillosis, as well as some other mold infections. However, it presents some pharmacokinetic singularities that lead to a great variability intra- and interindividually, nonlinear pharmacokinetics, and a narrow therapeutic range. Most experts have recommended tracing the levels of voriconazole in patients when receiving treatment. This azole is metabolized through the hepatic enzyme complex cytochrome P450 (CYPP450), with the isoenzyme CYP2C19 being principally involved. Allelic variations (polymorphisms) of the gene that encodes this enzyme are known to contribute to variability in voriconazole exposure. Three different allelic variants, CYP2C19*17, CYP2C19*2, and CYP2C19*3, could explain most of the phenotypes related to the voriconazole metabolism and some of its pharmacokinetic singularities. We designed a rapid molecular method based on high-resolution melting to characterize these polymorphisms in a total of 142 samples, avoiding sequencing. Three PCRs were designed with similar cycling conditions to run simultaneously. The results showed that our method represents a fast, accurate, and inexpensive means to study these variants related to voriconazole metabolism. In clinical practice, this could offer a useful tool to individually optimize therapy and reduce expenses in patients with fungal infections.