RESUMO
The Hepatitis B virus (HBV) is the prototype member of the Hepadnaviridae family, which can cause acute or chronic hepatic illness. The virus has a partially double-stranded DNA genome of3.2 kb. Molecular variations and change in the genome over time have resulted in the emergence of at least eight genotypes and multiple subgenotypes. The distribution of HBV genotypes varies widely across geographic regions, been the genotype F the most prevalent in Chile. In recent years, substantial progress has been made toward understanding the epidemiology and virologic significance of HBV variants. Actually, accumulating evidence suggests that hepatitis B genotypes and subgenotypes can influence the severity, course and likelihood of complications, and response to treatment of HBV infection and possibly vaccination against the virus.