Diseases Studied
The Rare Diseases Clinical Research Network is an NIH-funded research network of 19 active consortia or research groups working to advance treatment for diseases that are rare. Use the search tools on this page to find the diseases we currently study. You can reach out to the indicated consortia or research groups for more information on those diseases and studies underway.
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All Diseases > Ornithine translocase deficiency
Ornithine translocase deficiency
Alternative Names: HHH Syndrome, Hyperornithinemia-Hyperammonemia-Homocitrullinuria Syndrome
Disease Category: Urea Cycle Disorders
An inherited, metabolic, urea cycle disorder characterized by homocitrulline excretion in urine as well as hyperornithinemia and hyperammonemia (high blood ornithine and ammonia levels, respectively). These signs are due to deficiency or absence of an enzyme needed to convert nitrogen from protein metabolism (break down) into urea (a waste product). Symptoms include vomiting, feeding and growth problems, fatigue, seizures, respiratory distress, liver problems, spasticity (muscle stiffness), coma, ataxia (lack of coordination), developmental delay, and cognitive impairment.