<prompt> Pyrimidine overproduction results in all exceptHyperuricemiaReye syndromeorotic aciduriaMegaloblastic anemia  <response>: Defective enzyme of pyrimidine metabolism Signs and symptoms Dihydropyrimidine dehydrogenase Can develop toxicity to 5-fluorouracil, also a substrate for this dehydrogenase Orotate phosphoribosyl transferase and orotidylic acid decarboxylase Orotic acid aciduria type 1, megaloblastic anemia Orotidylic acid decarboxylase Orotic acid aciduria type 2 Pyrimidine overproduction is not the causal factor in Reyes syndrome. Reyes syndrome results in secondary pyrimidine overproduction. Reference: Harpers illustrated biochemistry 30th edition 