title: Epidemiological and virological characteristics of 2 subgroups of hepatitis B virus genotype C.
abstract: BACKGROUND
  We aimed to investigate the characteristics of hepatitis B virus (HBV) genotype C subgroups in Hong Kong and their relationship with HBV genotype C in other parts of Asia.
  
  
  METHODS
  Full-genome nucleotide sequences of 49 HBV genotype C isolates from Chinese patients with chronic hepatitis B were compared with the sequences of 69 HBV genotype C isolates and 12 non-genotype C isolates in the GenBank database. Phylogenetic analysis was performed to define the subgroups of HBV genotype C on the basis of >4% heterogeneity of the entire HBV genome.
  
  
  RESULTS
  HBV in 80% of patients in Hong Kong belonged to a subgroup predominantly found in Southeast Asia (Vietnam, Thailand, Myanmar, and southern China) designated as HBV genotype "Cs," and HBV in the remaining 20% of patients belonged to another subgroup, predominantly found in the Far East (Korea, Japan, and northern China), designated as HBV genotype "Ce." Overall, the mean+/-SD nucleotide sequence difference between HBV genotype Cs and HBV genotype Ce was 4.2%+/-0.3%. When HBV genotype Cs and HBV genotype Ce were compared among patients in Hong Kong, HBV genotype Cs was associated with a higher tendency to develop basal core promoter mutations (80% vs. 50%; P=.14), a higher prevalence of C at nucleotide 1858 (95% vs. 0%; P<.001), and a lower prevalence of precore stop codon mutations (5% vs. 50%; P=.002).
  
  
  CONCLUSIONS
  HBV genotype C can be differentiated into 2 subgroups--namely, genotype Ce and genotype Cs--that have different epidemiological distributions and virological characteristics.
authors.affiliation: Department of Medicine and Therapeutics, The Chinese University of Hong Kong, Hong Kong Special Administrative Region, People's Republic of China. hlychan@cuhk.edu.hk
authors.forename: Henry L Y
authors.initials: HL
authors.lastname: Chan
authors.forename: Stephen K W
authors.initials: SK
authors.lastname: Tsui
authors.forename: Chi-Hang
authors.initials: CH
authors.lastname: Tse
authors.forename: Eddie Y T
authors.initials: EY
authors.lastname: Ng
authors.forename: Thomas C C
authors.initials: TC
authors.lastname: Au
authors.forename: Lilly
authors.initials: L
authors.lastname: Yuen
authors.forename: Angeline
authors.initials: A
authors.lastname: Bartholomeusz
authors.forename: Kwong-Sak
authors.initials: KS
authors.lastname: Leung
authors.forename: Kin-Hong
authors.initials: KH
authors.lastname: Lee
authors.forename: Stephen
authors.initials: S
authors.lastname: Locarnini
authors.forename: Joseph J Y
authors.initials: JJ
authors.lastname: Sung
mesh_terms: D000328:Adult; D005260:Female; D005838:Genotype; D006509:Hepatitis B / Q000453:epidemiology* / Q000821:virology*; D006515:Hepatitis B virus / Q000145:classification / Q000235:genetics*; D006723:Hong Kong / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010802:Phylogeny