Determination of -3858G-->A and -164C-->A genetic polymorphisms of CYP1A2 in blood and saliva by rapid allelic discrimination: large difference in the prevalence of the -3858G-->A mutation between Caucasians and Asians

Introduction Two mutations in CYP1A2, –164CA (allele CYP1A2*F) and –3858GA (allele CYP1A2*C), affecting the inducibility of the enzyme, have been published. The aim of this study was to develop a high throughput allelic discrimination assay for these mutations in both saliva and blood and to determine their frequency in Caucasians.Methods An allelic discrimination assay, based on the fluorogenic 5-nuclease activity (TaqMan), was developed for the two mutations. Genomic DNA extracted from 17 saliva and 100 blood samples from Caucasians was analysed.Results and conclusions For the –164CA mutation, we found an allelic frequency of 68% in the Caucasian population, comparable with data published for Asians and Caucasians. For the –3858GA mutation, the allele frequency was only 2% in Caucasians, a much lower value than the ~25% reported in Asians (P<0.001). The presented allelic discrimination allows fast and accurate detection of these two mutations. Genotype calls were 100% identical for DNA from saliva and blood. Saliva is easily accessible and represents an excellent alternative to the traditionally used venous blood for genotyping.