title: Hepatitis B virus infection in children, adolescents, and their relatives: genotype distribution and precore and core gene mutations.
abstract: BACKGROUND
  The objectives of this study were evaluate hepatitis B virus (HBV) serological markers in children and adolescents followed up at the Child Institute of the Hospital das Clínicas, Faculdade de Medicina de São Paulo, Universidade de São Paulo; identify chronic HBV carriers and susceptible individuals in the intrafamilial environment; characterize HBV genotypes; and identify mutations in the patients and household contacts.
  
  
  METHODS
  Ninety-five hepatitis B surface antigen-positive children aged <19 years and 118 household contacts were enrolled in this study. Commercial kits were used for the detection of serological markers, and PCR was used for genotyping.
  
  
  RESULTS
  Hepatitis B e antigen (HBeAg) was detected in 66.3% (63/95) of cases. Three of the 30 HBeAg-negative and anti-HBeAg-positive patients presented with precore mutations and 11 presented with mutations in the basal core promoter (BCP). Genotype A was identified in 39 (43.8%) patients, genotype D in 45 (50.6%), and genotype C in 5 (5.6%). Of the 118 relatives, 40 were chronic HBV carriers, 52 presented with the anti-HBc marker, 19 were vaccinated, and 7 were susceptible. Among the relatives, genotypes A, D, and C were the most frequent. One parent presented with a precore mutation and 4 presented with BCP mutations.
  
  
  CONCLUSIONS
  Genotypes A and D were the most frequent among children, adolescents, and their relatives. The high prevalence of HBV in the families showed the possibility of its intrafamilial transmission.
authors: Laboratório de Hepatites Virais, Instituto Adolfo Lutz, São Paulo, SP, Brasil. adri_parise@yahoo.com
authors: Adriana Parise
authors: AP
authors: Compri
authors: Irene
authors: I
authors: Miura
authors: Gilda
authors: G
authors: Porta
authors: Marcilio Figueiredo
authors: MF
authors: Lemos
authors: Cláudia Patara
authors: CP
authors: Saraceni
authors: Regina Célia
authors: RC
authors: Moreira
mesh_terms: D000293:Adolescent; D002353:Carrier State; D002648:Child; D002675:Child, Preschool; D016358:Contact Tracing; D004279:DNA, Viral / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D005190:Family; D005260:Female; D005838:Genotype; D006510:Hepatitis B Antibodies / Q000097:blood; D006513:Hepatitis B e Antigens / Q000097:blood; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000635:transmission / Q000821:virology*; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D055815:Young Adult
chemical_list: D004279:DNA, Viral; D006510:Hepatitis B Antibodies; D006513:Hepatitis B e Antigens