Abstract
Activity of the enzyme uroporphyrinogen III cosynthetase in hemolysates from human or bovine subjects with cogential erythropoietic porphyria is much lower than the activity in control hemolysates. The partial deficiency of cosynthetase is probably a primary genetic defect in this discase and explains the pathological overproduction of uroporphyrin I. Cosynthetase activity in hemolysates from asymptomatic bovine carriers of prophyria are intermediate to those of normal and porphyric animals. This observation is consistent with the known autosomal recessive mode of inheritance of the disorder. Similarly, in two human families parents or children of the porphyric propositus had the cosynthetase activities expected for a heterozygote state; but in a third family, these activities were in the normal range. Hence, they may be some genetic heterogeneity in the human disease. Also, the specific activity of cosynthetase is lower in extracts of fibroblasts grown in tissue culture from skin biopsies taken from patients with porphyria than in similar extracts from non-porphyric cells. This indicates that although the metabolic error in porphyrin formation is expressed only in erythropoietic tissue, the hereditary defect in the enzyme activity occurs in other tissues as well.
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Romeo, G., Kaback, M., Glenn, B. et al. The Enzymatic Defect in Congenital Erythropoietic Porphyria: Demonstration in Heterozygotes and in Non-erythropoietic Tissue of Homozygotes. Pediatr Res 4, 465 (1970). https://doi.org/10.1203/00006450-197009000-00124
Issue Date:
DOI: https://doi.org/10.1203/00006450-197009000-00124