An extremely rare autosomal recessive inherited disorder caused by mutations in the UMPS gene. It is characterized by deficiency of the activity of the pyrimidine pathway enzyme uridine 5'-monophosphate (UMP) synthase. Clinical manifestations include growth retardation, anemia, and increased excretion of orotic acid in the urine. The disease is orotic aciduria (MONDO_0009797, a Monarch Disease Ontology id). Also known as: Hereditary Orotic Aciduria, oroticaciduria, orotidylic decarboxylase deficiency, uridine monophosphate synthetase deficiency.