Deficiencies in the attachment of PRPP to orotate (or the decarboxylation of orotate monosphosphate) can result in the accumulation of orotic acid; similarly deficiencies of the urea cycle, which lead...Deficiencies in the attachment of PRPP to orotate (or the decarboxylation of orotate monosphosphate) can result in the accumulation of orotic acid; similarly deficiencies of the urea cycle, which lead to an accumulation of carbamoyl phosphate, can increase flux through pyrimidine synthesis and cause an increase in orotic acid.