Association of genetic variations in GNB1 with response to peginterferon plus ribavirin therapy for chronic hepatitis C in a Chinese population in Taiwan

BACKGROUND The aim of this study was to evaluate whether polymorphisms in the guanine nucleotide binding (G protein), beta polypeptide 1 (GNB1) gene are associated with a rapid virological response (RVR) among HCV genotype 1 (HCV-1) and 2 (HCV-2) infected patients receiving peginterferon plus ribavirin treatment (PEG-IFNα-RBV). METHODS We analyzed the association between RVR to PEG-IFNα-RBV therapy and 4 tagging single nucleotide polymorphisms (SNPs) of the GNB1 gene. This study included 265 HCV-1 and 195 HCV-2 infected patients in a Chinese population in Taiwan. RESULTS Among the GNB1 SNPs examined, the combination of genotypes G/G and G/T populations of rs12126768 was significant inversely correlated with RVR in HCV-1 infected patients (P = 0.0330), whereas HCV-2 infected patients, combination of A/A and A/C genotypes populations at rs4648727 responded better to the PEG-IFNα-RBV treatment (P = 0.0089). However, there were no significant differences in the allele frequencies of those SNPs between RVR responders and non-responders. Several RVR susceptibility GNB1 haplotypes were identified, and the ACAT haplotype of the 4 SNPs may increase the successful outcomes of HCV-1 and HCV-2 infected patients (P = 0.0261 and P = 0.0253, respectively). CONCLUSION The data for GNB1 SNPs and the association of RVR showed that GNB1 polymorphisms might be associated with the therapeutic outcomes of HCV-1 and HCV-2 infected patients under standard of care (SOC) treatment.