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Updated: Apr 23, 2026

Isolation of Fidelity Variants of RNA Viruses and Characterization of Virus Mutation Frequency
Published on: June 16, 2011
Effect of drug resistance mutations on antiviral agents in HCV patients
Grey Liu1, Qingxian Cai, Zhanyi Li
1The Department of Infectious Disease, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
Background:
Gene polymorphism of HCV is an important cause of drug resistance to direct-acting antivirals (DAAs).
Methods:
Nested PCR assays were performed to amplify the HCV viral regions of NS3, NS5A and NS5B.
Results:
Major resistant mutation A156S was found in 18.33% of patients with HCV-1b and 64.28% of patients with HCV-2a. HCV-6a patients had a Q80K mutation rate of 95.45%, while the mutation rate of V170I was up to 100%. Mutation frequency varied with the different genotypes of HCV. The proportion of four resistance mutations (M36L, Q80K, A156S, V170I) in different groups were statistically significant (P<0.05). Resistant mutation Q30R was detected in 116 (72.5%) samples with HCV-1b and -6a, L31M was found in 16 patients, including 12 with HCV-2a and 4 with HCV-6a, H58P was discovered in 42.5% (68/160) of patients with the genotypes Q30R, L31M and H58P; Y93C was found in 9individuals with only HCV-2a. In HCV NS5B sequences, only a few resistant variants were detected, including C316N and S282T.
Conclusions:
Naturally occurring dominant resistance mutations to HCV DAAs pre-existed in treatment-naive patients in China. Mutation frequency and characteristics varied with the HCV genotype.
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