A urea cycle disorder (UCD) is a rare disease in which the urea cycle does not function correctly due to a defective or missing enzyme or transporter.1-4 The resulting elevated ammonia levels may have significant consequences if left untreated.4
This site is a resource for healthcare professionals to learn more about UCDs, to get support for their patients, and to locate a Metabolic Specialist.
Review information about how a UCD may present in patients
Consult with a specialist experienced in diagnosing and treating UCDs
Lethargy, headaches, vomiting, protein avoidance, and poor appetite are signs that your patient may have elevated ammonia levels due to an undiagnosed UCD.5-7
1. Batshaw ML, Tuchman M, Summar M, Seminara J; Members of the Urea Cycle Disorders Consortium. A longitudinal study of urea cycle disorders. Mol Genet Metab. 2014;113(1-2):127-130. 2. Cohn RM, Roth KS. Hyperammonemia, bane of the brain. Clin Pediatr (Phila). 2004;43(8):683-689. 3. Summar ML, Dobbelaere D, Brusilow S, Lee B. Diagnosis, symptoms, frequency and mortality of 260 patients with urea cycle disorders from a 21-year, multicentre study of acute hyperammonaemic episodes. Acta Paediatr. 2008;97(10):1420-1425. 4. Ah Mew N, Simpson KL, Gropman AL, Lanpher BC, Chapman KA, Summar ML. Urea Cycle Disorders Overview. In: Adam MP, Mirzaa GM, Pagon RA, et al., eds. GeneReviews®. University of Washington; 2003. 5. Matsumoto S, Häberle J, Kido J, Mitsubuchi H, Endo F, Nakamura K. Urea cycle disorders-update. J Hum Genet. 2019;64(9):833-847. 6. Stone WL, Basit H, Jaishankar GB. Urea Cycle Disorders. StatPearls Publishing; 2022. 7. Häberle J, Burlina A, Chakrapani A, et al. Suggested guidelines for the diagnosis and management of urea cycle disorders: first revision. J Inherit Metab Dis. 2019;42(6):1192-1230.
