Hereditary orotic aciduria was found in a 7-year-old girl who had anemia, leukopenia, a megaloblastic bone marrow, crystalluria, and normal growth and intelligence. Uridine produced a rapid hematologic improvement, similar to that seen in the previously reported cases. The 24-hour excretion of urinary orotic acid ranged from 290 mg while the patient was on a dosage of 150 mg/kg/day of uridine, to 650 mg while she was on a dosage of 20 mg/ kg/day. The urinary orotic acid/creatinine ratio varied inversely with the uridine dose. Enzyme studies on hemolysates and cultured fibroblasts from the patient revealed grossly reduced levels of orotidine-5′-monophosphate pyrophosphorylase and decarboxylase. The red blood cell levels of both of these enzymes in the one parent studied were compatible with heterozygosity.
Tubergen DG, Krooth RS, Heyn RM. Hereditary Orotic Aciduria With Normal Growth and Development. Am J Dis Child. 1969;118(6):864–870. doi:10.1001/archpedi.1969.02100040866009
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