Chemically induced congenital thymic dysgenesis in the rat: a model of the DiGeorge syndrome.

The DiGeorge syndrome, a variable complex of thymic aplasia, congenital heart disease, hypoparathyroidism, and anomalies of the face and neck, is thought to result from exposure to teratogenic agents. A group of congenital defects closely resembling this syndrome can be produced in newborn rats by the administration of the fat-soluble zinc chelating agent WIN 18,446, a bis-dichloroacetylamine. This drug, nontoxic to adult animals, is a powerful teratogen when administered to pregnant rats during days 9-12 of the 21-day gestation period. Our animal data suggest that the human syndrome results from exposure in utero to agents like WIN 18,446, which damage the fetus during a critical period of organogenesis.