548 PRENATAL DIAGNOSIS OF CONGENITAL ERYTHROPOIETIC ETIC PORPHYRIA

Abstract

Congenital erythropoietic porphyria (CEP) is a rare disorder of porphyrin metabolism in which uroporphyrinogen I (Uro I) and coproporphyrinogen I are found in great excess in tissues and excreta. This autosomal recessive disorder has been atributed to a partial deficiency of Uro III cosynthetase activity in cells of erythroid origin and other tissues. Studies of fibroblast cultures from skin of a 2 year old boy with CEP revealed an accumulation of protoporphyrin after incubation with Δ-amino-levulinic acid, but no increase in Uro I. A pregnancy of the mother of the patient with CEP was monitored by amniocentesis at 16 weeks gestation. The amniotic fluid had a pink-brown discoloration, and extraction of the porphyrins revealed a marked increase in fluorescence in comparison with control fluids, with characteristic absorption and emission spectra. The presence of marked excess of Uro I was confirmed by thin layer chromatography. Prostaglandin termination of pregnancy 4 days later confirmed the presence of excess Uro I in fetal tissues. Although the diagnosis of CEP can be confirmed by demonstration of reduced Uro III cosynthetase activity in amniotic cell cultures, the marked derangement of Uro I formation is evident in amniotic fluid thereby facilitating prenatal diagnosis of this disorder. (Supported by NIH Grant GM 19100)