title: Effect of drug resistance mutations on antiviral agents in HCV patients.
abstract: Gene polymorphism of HCV is an important cause of drug resistance to direct-acting antivirals (DAAs).
  
  
  
  Nested PCR assays were performed to amplify the HCV viral regions of NS3, NS5A and NS5B.
  
  
  
  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.
  
  
  
  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.
authors.affiliation: The Department of Infectious Disease, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China.
authors.forename: Grey
authors.initials: G
authors.lastname: Liu
authors.forename: Qingxian
authors.initials: Q
authors.lastname: Cai
authors.forename: Zhanyi
authors.initials: Z
authors.lastname: Li
authors.forename: Xiaoqiong
authors.initials: X
authors.lastname: Shao
authors.forename: Qiumin
authors.initials: Q
authors.lastname: Luo
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhixin
authors.initials: Z
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D000328:Adult; D000998:Antiviral Agents / Q000494:pharmacology*; D024882:Drug Resistance, Viral / Q000235:genetics*; D005260:Female; D005838:Genotype; D016174:Hepacivirus / Q000145:classification / Q000187:drug effects* / Q000235:genetics*; D019698:Hepatitis C, Chronic / Q000188:drug therapy* / Q000821:virology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009154:Mutation; D059645:Mutation Rate; D017361:Viral Nonstructural Proteins / Q000235:genetics; D055815:Young Adult; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; D012324:RNA-Dependent RNA Polymerase
chemical_list: D000998:Antiviral Agents; D017361:Viral Nonstructural Proteins; C084422:NS3 protein, hepatitis C virus; D012697:Serine Endopeptidases; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases; C087036:NS-5 protein, hepatitis C virus; D012324:RNA-Dependent RNA Polymerase