PMID- 16622876
OWN - NLM
STAT- MEDLINE
DCOM- 20060828
LR  - 20220409
IS  - 0146-6615 (Print)
IS  - 0146-6615 (Linking)
VI  - 78 Suppl 1
DP  - 2006
TI  - Hepatitis B virus genetic diversity.
PG  - S36-42
AB  - Hepatitis B virus (HBV) is a human DNA virus, which replicates through an RNA 
      intermediate because of the reverse-transcriptase (RT) activity of its DNA 
      polymerase. As a result, the mutation rate for HBV is higher than the rate 
      observed for most DNA viruses. HBVs are classified into genotypes based on 
      genomic sequencing, and antigenic subtypes based on the antigenic properties of 
      its major surface glycoprotein, the HBV surface antigen (HBsAg). Subgenotypes 
      have been identified within most of the HBV genotypes. The HBV groups defined by 
      the different genotype-HBsAg subtype associations found over the world display 
      characteristic geographical distributions, reflecting the movements of human 
      populations and other epidemiologically significant events. Such HBV groups 
      constitute genetically stable viral populations sharing a common evolutionary 
      history, but additional stable changes, originating from mutation and mutant 
      selection, are observed within all of them. These viral sub-populations are known 
      as the HBV variants, and some of which have medical and public health relevance. 
      Pre-core (pre-C) defective variants have been shown to make HBV infection much 
      less susceptible to interferon treatment, and treatment failures with other 
      antiviral drugs have been associated with selection of resistant variants that 
      display specific mutations in the genome region encoding the viral RT activity. 
      Since the RT region of the genome overlaps the sequence encoding the HBsAg 
      molecule, selection of drug resistant variants involves, in some cases, the 
      indirect selection of HBsAg variants. Viral variants displaying changes in HBsAg 
      seem to be very common among chronic HBV carriers; and some of these variants may 
      emerge under the pressure of the neutralizing antibody response, leading to 
      vaccine resistance and resistance to immunotherapy. Mutations conferring 
      resistance to immunotherapy are noted often among liver transplant recipients and 
      among babies born to HBV-carrier mothers. In addition, some of these HBsAg 
      variants have been associated with lack of detection by HBsAg tests used for the 
      diagnosis of HBV infection, for the identification of chronic carriers, for 
      screening of blood donations for transfusion, and in the manufacture of 
      therapeutic blood products.
FAU - Echevarria, Jose M
AU  - Echevarria JM
AD  - Service of Diagnostic Microbiology, National Centre of Microbiology, Instituto de 
      Salud Carlos III, Madrid, Spain. jmecheva@isciii.es
FAU - Avellon, Ana
AU  - Avellon A
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Med Virol
JT  - Journal of medical virology
JID - 7705876
RN  - 0 (Antiviral Agents)
RN  - 0 (Hepatitis B Surface Antigens)
RN  - EC 2.7.7.49 (RNA-Directed DNA Polymerase)
SB  - IM
MH  - Antiviral Agents/pharmacology
MH  - Carrier State/virology
MH  - Drug Resistance, Viral
MH  - Evolution, Molecular
MH  - Genetic Variation
MH  - Genome, Viral
MH  - Hepatitis B/diagnosis/drug therapy/*virology
MH  - Hepatitis B Surface Antigens/classification/genetics
MH  - Hepatitis B virus/classification/drug effects/*genetics
MH  - Hepatitis B, Chronic/virology
MH  - Humans
MH  - Liver Transplantation/adverse effects
MH  - Mutation
MH  - RNA-Directed DNA Polymerase/genetics/metabolism
EDAT- 2006/04/20 09:00
MHDA- 2006/08/29 09:00
CRDT- 2006/04/20 09:00
PHST- 2006/04/20 09:00 [pubmed]
PHST- 2006/08/29 09:00 [medline]
PHST- 2006/04/20 09:00 [entrez]
AID - 10.1002/jmv.20605 [doi]
PST - ppublish
SO  - J Med Virol. 2006;78 Suppl 1:S36-42. doi: 10.1002/jmv.20605.