Prenatal diagnosis of lobar holoprosencephaly.

Lobar holoprosencephaly was identified with sonography in 12 fetuses between 21 and 35 weeks' gestation. A confident diagnosis was made in each case by a mid-coronal view of the brain demonstrating absence of the cavum septum pellucidum with fusion and squaring of the frontal horns. The only associated anomaly was Dandy-Walker malformation that occurred in three cases. All fetuses had mild to severe ventriculomegaly. Five pregnancies were terminated; there was one spontaneous abortion and six fetuses were delivered at term. A ventriculo-peritoneal shunt was implanted in four. Follow-up was available for five and revealed severe mental retardation in each case. Lobar holoprosencephaly is amenable to prenatal ultrasound diagnosis, although a differentiation with other cerebral malformations may be difficult at times. The outcome of affected infants remains uncertain, but neurological impairment occurs frequently. Copyright 1992 International Society of Ultrasound in Obstetrics and Gynecology