title: Emergence of YMDD motif mutant of hepatitis B virus during short-term lamivudine therapy in South Korea.
abstract: OBJECTIVE
  The emergence of a YMDD mutant resistant to lamivudine therapy has been reported in patients with hepatitis B treated with long-term lamivudine therapy. However, it is not well known whether the YMDD mutant could be detected early in lamivudine therapy in hepatitis B virus (HBV) endemic areas. The aim of this study was to investigate the emergence of the YMDD mutant during short-term lamivudine therapy in South Korea.
  
  
  METHODS
  We prospectively investigated the emergence of the YMDD mutant by the nested PCR assay using restriction fragment length polymorphism in 28 patients with chronic hepatitis B who were treated with 100 mg of lamivudine daily for 12 weeks.
  
  
  RESULTS
  The YMDD mutant was detected in 17 (60.7%) out of 28 patients at week 12, and the only type of mutation found was the YIDD mutation. When we carried out the nested PCR serially in five patients, YIDD mutants were detected as early as 2 weeks by the nested PCR assay. The nested PCR results were in concordance with DNA sequencing in one patient's serial samples.
  
  
  CONCLUSIONS
  YMDD mutants in HBV were detected within a few weeks during lamivudine therapy in South Korea, which suggests that the YMDD mutant may exist even before lamivudine therapy in HBV endemic areas.
authors.affiliation: Department of Internal Medicine, Institute of Gastroenterology, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Y H
authors.initials: YH
authors.lastname: Paik
authors.forename: H Y
authors.initials: HY
authors.lastname: Chung
authors.forename: W S
authors.initials: WS
authors.lastname: Ryu
authors.forename: K S
authors.initials: KS
authors.lastname: Lee
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: J H
authors.initials: JH
authors.lastname: Kim
authors.forename: C K
authors.initials: CK
authors.lastname: Lee
authors.forename: C Y
authors.initials: CY
authors.lastname: Chon
authors.forename: Y M
authors.initials: YM
authors.lastname: Moon
authors.forename: K H
authors.initials: KH
authors.lastname: Han
mesh_terms: D000328:Adult; D004279:DNA, Viral / Q000235:genetics; D004334:Drug Administration Schedule; D004352:Drug Resistance, Microbial / Q000235:genetics*; D005260:Female; D006509:Hepatitis B / Q000188:drug therapy*; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007723:Korea; D019259:Lamivudine / Q000008:administration & dosage / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D011446:Prospective Studies; D018894:Reverse Transcriptase Inhibitors / Q000008:administration & dosage / Q000627:therapeutic use*; D017422:Sequence Analysis, DNA; D013997:Time Factors
chemical_list: D004279:DNA, Viral; D018894:Reverse Transcriptase Inhibitors; D019259:Lamivudine