Transmission of G145R mutant of HBV to an unrelated contact

Abstract

Household contacts of HBV-related chronic liver disease patients constitute a high-risk group for acquisition of HBV infection. Some of the HBsAg mutants are associated with liver disease and some are reported to be transmitted vertically. There is limited information on the horizontal transmission of Gly 145 Arg (G145R) mutant to related contacts. Its possible transmission to an unrelated third degree contact is reported in the present study. An HBV related chronic liver disease patient; the index patient, and his 11 household contacts were studied. This included four 1°, three 2°, one 3°, and a sexual contact. Surface gene sequencing including the "a"determinant region was carried out in HBV DNA+ve subjects. The sequences were aligned and compared for the homology. HBV DNA was found to be positive in one 1°, three 2°, and one 3° contact, besides the index patient. Histopathological studies revealed evidence of chronic hepatitis in all these contacts. Mutation T118V was present in all the six subjects. Mutant G145R along with T118V and T143M was identified in three subjects who included one 1°, one 2°, and one 3° contact. Presence of T118V and T143M mutations along with G145R mutation in these subjects provides an indirect evidence for the possible horizontal transmission of G145R HBV variant to a 3° unrelated contact. Of these three contacts with G145R mutation, only one 1° contact was found to be HBsAg-ve. The data also reaffirms the earlier finding of HBsAg positivity in presence of G145R mutation of the S-gene. HBV exists as quasi-species and mixed population in subjects with chronic HBV infection.