ABSTRACT
<p><b>OBJECTIVE</b>In order to investigate the characterization of mother to children transmission, the sequences of HBV were analyzed to offer the information about the effect of interrupt.</p><p><b>METHODS</b>The sera of 75 mother with positive HBsAg are collected from 2003, and the ELISA was performed to determine the HBV infection of the child. The Large S sequence of HBV including preS and S gene are amplified and sequenced. The genotype was determined with the standard genotype sequence. The mutation ratios of group successfully interrupted and failed compared.</p><p><b>RESULTS</b>The sera of 4 pairs mother-children were HBsAg positive, including one twins. The virus genes are successful amplified. Four of HBV genotype is B and one is C. Gene of twins has mutation of T143M. 43 HBV of successfully interrupted group were sequenced. There are 37 of genotype B and 6 of genotype C. Three have the mutation in "a" dominant, and the percentage is 7%.</p><p><b>CONCLUSION</b>Most failed interrupted child have the same sequence with their mother, and the ratio is higher than the mother of successful group, however there have no statistical significance.</p>