Allelic inhibition of displacement activity: a simplified one tube allele-specific PCR for evaluation of ITPA polymorphisms.

Recently, genome-wide association studies (GWAS) in patients with chronic hepatitis C virus (HCV) infection have identified two functional single nucleotide polymorphisms (SNPs) in the inosine triphosphatase (ITPA) gene, that are associated strongly and independently with hemolytic anemia in patients exposed to pegylated-interferon (Peg-IFN) plus ribavirin (RBV) combined therapy. Here has been developed a simplified allele discrimination polymerase chain reaction (PCR) assay named allelic inhibition of displacement activity (AIDA) for evaluation of ITPA polymorphisms. AIDA system relies on three unlabeled primers only, two outer common primers and one inner primer with allele-specific 3' terminus mismatch. DNA samples from 192 patients with chronic HCV infection were used to validate the AIDA system and results were compared with the gold standard TaqMan(®) SNP genotyping assay. Concordant data were obtained for all samples, granting for high specificity of the method. In conclusion, AIDA is a practical one-tube method to reproducibly and to assess accurately rs7270101 and rs1127354 ITPA SNPs.