Differential clinical manifestations of congenital cytomegalovirus infection between dizygotic twins: a case report.

To understand a mechanism for the difference in clinical manifestations of congenital cytomegalovirus (CMV) infection between dizygotic twins, the placentas of the dizygotic twins were evaluated for the number of the cells infected with CMV by immunohistochemical and in situ hybridization studies. A Japanese woman with dizygotic twin pregnancy had immunoglobulin M antibodies to CMV at 15 weeks gestation. Intrauterine growth retardation was noted only in the first twin. At birth, CMV was isolated from urine culture in both twins. Clinical manifestations for CMV, such as petechiae, jaundice, hepatosplenomegaly, and deafness were more pronounced in the first twin than in the second twin. Immunohistochemical and in situ hybridization studies showed CMV-positive cells two or three times more densely distributed in the placenta of the first twin compared with the second twin. These data suggest the severity of CMV manifestations of dizygotic twins may be in accord with the number of CMV-positive cells in the placenta.