Hereditary Orotic Aciduria

**Semantic type:** Disease or Syndrome

**Definition:** 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.