Acquired craniofacial features associated with chronic phenytoin therapy.

Although the teratogenic effect of phenytoin on the fetus has been well-documented, the effect on postnatal facial structure has not been emphasized. The evolution of such changes is illustrated with serial photographs and case histories of five mentally retarded individuals not known to have diagnoses that could account for these dysmorphic features. The intent of this report is to increase awareness of this serious consequence of phenytoin therapy and to stimulate interest in further studies of the phenomenon. The incidence and prevalence, mechanism of production, genetic predisposition, and critical age for development of this effect in patients treated with phenytoin needs to be determined.