title: Children with Chronic Hepatitis B in the United States and Canada.
abstract: OBJECTIVE
  To test the hypothesis that children with chronic hepatitis B living in the US and Canada would have international origins and characteristic hepatitis B virus (HBV) genotypes and laboratory profiles.
  
  
  METHODS
  Clinical characteristics of children enrolled in the Hepatitis B Research Network were collected from 7 US and Canadian centers.
  
  
  RESULTS
  Children (n = 343) with an age range of 1.0-17.8 years were enrolled; 78% of the children were Asian, 55% were adopted, and 97% had international origins with either the child or a parent born in 1 of 31 countries. The majority had HBV genotype B (43%) or C (32%), and the remainder had genotype A (5%), D (16%), E (4%), or multiple (<1%). Children with genotype B or C were more likely to be Asian (98% and 96%), more consistently hepatitis B envelope antigen positive (95% and 82%), had higher median HBV DNA levels (8.2 and 8.3 log10 IU/mL), and less frequently had elevated alanine aminotransferase values (43% and 57%) compared with children with other genotypes. The percentage of hepatitis B envelope antigen positivity and of those with HBV DNA ≥6 log₁₀ IU/mL declined with age.
  
  
  CONCLUSIONS
  The majority of children in the Hepatitis B Research Network have HBV genotypes that reflect their international origins. Clinical and laboratory data differ substantially by patient age and HBV genotype. Use of these data can help drive the development of optimal strategies to manage and treat children with chronic hepatitis B.
authors.affiliation: Department of Pediatrics, Johns Hopkins Medical Institutions, Baltimore, MD. Electronic address: kschwarz@jhmi.edu.
authors.forename: Kathleen B
authors.initials: KB
authors.lastname: Schwarz
authors.affiliation: Department of Epidemiology, University of Pittsburgh, Pittsburgh, PA.
authors.forename: Yona Keich
authors.initials: YK
authors.lastname: Cloonan
authors.affiliation: Department of Pediatrics, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Simon C
authors.initials: SC
authors.lastname: Ling
authors.affiliation: Department of Pediatrics, University of Washington, Seattle, WA.
authors.forename: Karen F
authors.initials: KF
authors.lastname: Murray
authors.affiliation: Department of Pediatrics, University of Texas Southwestern, Dallas, TX.
authors.forename: Norberto
authors.initials: N
authors.lastname: Rodriguez-Baez
authors.affiliation: Department of Pediatrics, University of Minnesota, Minneapolis, MN.
authors.forename: Sarah Jane
authors.initials: SJ
authors.lastname: Schwarzenberg
authors.affiliation: Department of Pediatrics, Saint Louis University, Saint Louis, MO.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Teckman
authors.affiliation: Centers for Disease Control and Prevention, Atlanta, GA.
authors.forename: Lilia
authors.initials: L
authors.lastname: Ganova-Raeva
authors.affiliation: Department of Pediatrics, University of California, San Francisco, San Francisco, CA.
authors.forename: Philip
authors.initials: P
authors.lastname: Rosenthal
mesh_terms: D000293:Adolescent; D002170:Canada / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D005260:Female; D005838:Genotype; D006515:Hepatitis B virus / Q000235:genetics*; D019694:Hepatitis B, Chronic / Q000453:epidemiology* / Q000235:genetics / Q000821:virology; D006801:Humans; D007223:Infant; D008297:Male; D014481:United States / Q000453:epidemiology