Discordant Expression of Fetal Hydantoin Syndrome in Heteropaternal Dizygotic Twins

Abstract

PRENATAL exposure to hydantoin analogues, including phenytoin, may result in the fetal hydantoin syndrome — a symptom complex characterized by poor growth and development with specific craniofacial and skeletal abnormalities.1 2 3 4 The full syndrome is seen in about 11 per cent of exposed infants, and an additional 31 per cent have partial expression of the teratogenic effects.1 The resulting dysmorphism is most striking at birth and generally becomes less pronounced with age, although the associated mental deficiency is permanent.2 Variability in the clinical manifestations of fetal hydantoin syndrome has been described in fraternal twins3 , 4 and triplets5 who were presumably exposed to . . .