Orotic aciduria

Orotic aciduria
Other namesOrotidylic pyrophosphorylase and orotidylic decarboxylase deficiency; Uridine monophosphate synthase (UMPS) deficiency
Structure of orotic acid
SpecialtyHematology 
SymptomsMegaloblastic anemia; developmental delays
CausesAutosomal recessive mutation of the UMPS gene
Differential diagnosisMitochondrial disorders; Lysinuric protein intolerance; liver disease
TreatmentUridine triacetate

Orotic aciduria (AKA hereditary orotic aciduria) is a disease caused by an enzyme deficiency, resulting in a decreased ability to synthesize pyrimidines. It was the first described enzyme deficiency of the de novo pyrimidine synthesis pathway.

Orotic aciduria patients lack the enzyme known as UMP synthase. Orotic aciduria is characterized by excessive excretion of orotic acid in urine because of the inability to convert orotic acid to UMP. It causes megaloblastic anemia and may be associated with mental and physical developmental delays.

Orotic aciduria is a rare disease. Fewer than 30 cases in human history have been reported in literature.