Orotic aciduria type 1

Orotic aciduria type I (OA1), also known as hereditary orotic aciduria, is a rare condition characterized by elevated levels of orotic acid in the urine. It typically becomes apparent in the first months of life with megaloblastic anemia, as well as delays in physical and intellectual development. OA1 is caused by changes (mutations) in the UMPS gene and inheritance is autosomal recessive. OA1 differs from other causes of orotic aciduria, which may include mitochondrial disorders, lysinuric protein intolerance, and liver disease.

Treatment involves taking uridine; uridine triacetate was granted FDA approval for treating OA1 in 2015. Without treatment, children with OA1 may experience neutropenia, failure to thrive, developmental delay, and intellectual disability.