Human cytomegalovirus gB genotype 1 is dominant in congenital infections in South Hungary.

On the basis of the sequence variation of the glycoprotein B (gB) gene, human cytomegalovirus (HCMV) can be classified into four gB genotypes. Genotyping of HCMV from congenital infections was carried out on the assumption that the envelope gB may influence the outcome of prenatal infection. Sixty-three pregnant women were included in the study: 40 pregnant women whose fetuses were strongly suspected of having viral infection, and 23 women with normal pregnancies, from whom amniotic fluid was taken for fetal karyotype assessment. The amniotic fluid, fetal blood, blood, and urine of the newborns were examined for HCMV DNA by a nested polymerase chain reaction, and the gB genotype was determined by restriction fragment length polymorphism. HCMV DNA was detected in 12 cases in which the fetuses were suspected of having a viral infection and in 3 of the normal pregnancies. All the HCMV DNA had identical genotype, gB1. These data clearly indicate the dominance of the gB1 genotype in congenital HCMV infections. The clinical outcome of these pregnancies, however, cannot be predicted on the basis of the involvement of this genotype.