Published online Apr 7, 2016. doi: 10.3748/wjg.v22.i13.3531
Peer-review started: October 30, 2015
First decision: November 27, 2015
Revised: December 13, 2015
Accepted: December 30, 2015
Article in press: December 30, 2015
Published online: April 7, 2016
Occult hepatitis B virus infection (OBI), characterized as the persistence of hepatitis B virus (HBV) surface antigen (HBsAg) seronegativity and low viral load in blood or liver, is a special form of HBV infection. OBI may be related mainly to mutations in the HBV genome, although the underlying mechanism of it remains to be clarified. Mutations especially within the immunodominant “α” determinant of S protein are “hot spots” that could contribute to the occurrence of OBI via affecting antigenicity and immunogenicity of HBsAg or replication and secretion of virion. Clinical reports account for a large proportion of previous studies on OBI, while functional analyses, especially those based on full-length HBV genome, are rare.
Core tip: With error-prone reverse transcription during replication, hepatitis B virus (HBV) displays a high rate of mutation, and a single mutation may affect the biological properties of HBV. Occult HBV infection (OBI) is a special form of HBV infection and a frequent phenomenon. Many previous publications have explored the association of OBI with the “hot spots” mutations that occur within the immunodominant “α” determinant of S proteins. However, there are no reviews available that elaborate on the relationship between OBI and mutations throughout the entire HBV genome. This review attempts to provide a comprehensive summary of HBV genetic variants that have been associated with OBI.