In Reply.—The role of ammonia metabolism in the pathogenesis of Reye syndrome and the exact nature of the implicated defect or defects in the urea cycle remain hypothetical, as indicated by the question in the title of my commentary. The fragmentary information available leaves open most of the possibilities suggested by the hypothesis described in that article, including the speculation that orotic acid may be responsible for the characteristic fatty changes observed in the liver of patients with Reye syndrome. Therefore, although the arguments put forward by Sinatra and co-workers may eventually be proved correct, the inadequate state of present knowledge precludes fixed positions on the subject.
The finding of normal urinary orotic acid excretion in a few patients with Reye syndrome does not exclude the possibility that orotic acid levels may become elevated very early in the course of the disease, then return rapidly to near-normal levels during
THALER MM. Reye Syndrome-Reply. Am J Dis Child. 1976;130(7):782. doi:10.1001/archpedi.1976.02120080103023