Hepatitis B virus infection in children, adolescents, and their relatives: genotype distribution and precore and core gene mutations

introduction: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 s？o paulo, universidade de s？o 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.