Epidemiological and virological characteristics of 2 subgroups of hepatitis B virus genotype C.
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.
Chan
Henry L Y
HL
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
Tsui
Stephen K W
SK
Tse
Chi-Hang
CH
Ng
Eddie Y T
EY
Au
Thomas C C
TC
Yuen
Lilly
L
Bartholomeusz
Angeline
A
Leung
Kwong-Sak
KS
Lee
Kin-Hong
KH
Locarnini
Stephen
S
Sung
Joseph J Y
JJ
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