Growth retardation, dysmorphic facies and minor malformations following massive exposure to phenobarbitone in utero

A syndrome of facial dysmorphism, pre- and postnatal growth deficiency, developmental delay and minor malformations is described in two siblings. The facial anomalies consist of short nose with low nasal bridge, hypertelorism, epicanthic folds, ptosis of eyelid (patient 2), lowset ears, wide mouth with protruding lips and relative prognathism. Patient 2 in addition had a cleft soft palate and a hypoplastic phalanx of his fifth fingers. Both siblings were exposed to extraordinary high levels of phenobarbitone (5.0-8.6 mg/100 ml) in utero. The same clinical picture has been reported by others following use of phenytoin in pregnancy, and the term "fetal hydantoin syndrome" has been proposed. Since the syndrome seems to occur both following exposure to phenytoin and to phenobarbital this term should probably be avoided. This interesting coincidence indicates that the drugs may have a similar mechanism of action on the development of the fetus.