COMPLEX GENOTYPE MIXTURES ANALYZED BY DEEP SEQUENCING IN TWO DIFFERENT REGIONS OF HEPATITIS B VIRUS GENOME. Hepatitis B virus

This study assesses the presence and outcome of genotype mixtures in the polymerase/surface and X/preCore regions of the HBV genome in patients with chronic hepatitis B virus (HBV) infection. Thirty samples from 10 chronic hepatitis B patients were included. The polymerase/surface and X/preCore regions were analyzed by deep sequencing (UDPS) in the first available sample at diagnosis, a pre-treatment sample, and a sample at treatment failure. HBV genotype was determined by phylogenesis. Quasispecies complexity was evaluated by mutation frequency and nucleotide diversity.The results provide evidence of genotype mixtures and differential genotype proportions in the polymerase/surface and X/preCore regions. The genotype dynamics in HBV infection and the different patterns of quasispecies complexity in the HBV genome suggest a new paradigm for HBV genotype classification.