Vol. 7, Issue 4 (2020)
Mutation at 243-G of 5′ untranslated region of HCV and its correlation with viral load in HCV infected individuals
Author(s): Priyanka Singh, Priyanka Tiwari, Ankita Roy
Abstract: The 5′untranslated region (UTR) of hepatitis C virus genome is highly conserved. Two distinct RNA elements, a longer internal ribosomal entry site and short 5′ proximal stem loop RNA are present within it. The 243-G nucleotide of HCV 5′ UTR present in the longer element is important for viral replication and translation. The aim of this study was to determine the mutation present at 243-G nucleotide of HCV genome among different population groups and its correlation with patient's viral load, an indication of in-vivo HCV replication. The variations associated with this mutation among host gender, viral genotype and different populations were also studied. 110 HCV sero-reactive blood samples were subjected to RNA detection and amplification of complete 5′ UTR followed by sequencing. The sequences were used for mutation, genotyping and phylogenetic analysis. It was found that HCV genotype 3a (56%) was the predominant type followed by 3b (20%), 1a (17.33%) and 1b (6.67%). Viral load was maximum (4.64 ±10.15) X 105 IU/ml in case of genotype 1b infected patients. In presence of G-243-A mutation, viral load decreased to 6.55 and 2.54-fold for genotype 1 and 3 respectively. Viral 243-G mutation within male individuals showed the highest decrease (2.51-fold) in viral load than females (1.7-fold). The overall decrease in viral load with G-243-A mutation was observed maximum (2.46-fold) within the thalassemia population. Thus, from our observations, viral load is host and viral genotype dependent and G-243-A mutation reduces the viral replication in-vivo. Importance The importance of our study is provided below: § This is the first in-vivo report stating that G-243-A mutation of 5´ UTR has a direct effect on viral load among the infected individuals. § Individuals irrespective of the population group with G-243-A mutation had a decreased viral load compared with the wild type. § Association between the G-243-A and viral load was dependent upon the individuals genotype and host gender. § Mutation rate was maximum among HCV genotype 1 (72.22%) than in genotype 3 (36.84%). § In presence of G-243-A mutation, viral load decreased to 6.55 and 2.54-fold for genotype 1 and 3 respectively. § Male individuals with G-243-A mutated virus showed the highest decrease (2.51-fold) in viral load compare to females (1.7-fold). Viral load was higher among HCV genotype 1 especially in genotype 1b infected individuals compared to genotype 3.