CHROMOSOME FRAGILE SITES IN MENTALLY RETARTED MALES - INCREASED INCIDENCE WITH SEIZURES AND DIPHENYLHYDANTOIN THERAPY

Chromosome fragile site or lesion data were examined in 154 institutio nalized mentally retarded males with or without seizures or treated wi th anti-seizure medication. Blood lymphocytes were cultured using thre e different cell culture conditions and the incidence of specific chro mosome fragile sites (10q25, 16q22, and 12q23) or lesions determined. Increased fragile sites were seen in mentally retarded males with seiz ures compared to those without seizures in cells grown in folate-deple te Medium 199. Those with seizures and treated with diphenylhydantoin had a higher incidence of induced fragile sites (p < 0.001) relative t o similar patients treated with antiseizure medication other than diph enylhydantoin. These results suggest that a cohort of patients with me ntal retardation and seizures are more likely to have induced cytogene tic changes when treated with diphenylhydantoin than mentally retarded individuals without seizures.