Urea Cycle Disorders: Clinical Presentation Outside the Newborn Period

Crit Care Clin. 2005 Oct;21(4 Suppl):S9-17. doi: 10.1016/j.ccc.2005.05.007.


Although most commonly associated with infancy, the majority of individuals with urea cycle disorders (UCDs) present outside the neonatal period, frequently in childhood. Signs and symptoms are often vague, but recurrent; fulminant presentations associated with acute illness are also common. A disorder of urea cycle metabolism should be considered in children who have recurrent symptoms, especially neurologic abnormalities associated with periods of decompensation. Routine laboratory tests, including measurement of plasma ammonia concentrations, can indicate a potential UCD; however, specific metabolic testing and ultimately enzymatic or molecular confirmation are necessary to establish a diagnosis. Treatment with dietary protein restriction and medications may be challenging in children.

Publication types

  • Case Reports
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Age of Onset
  • Amino Acid Metabolism, Inborn Errors* / diagnosis
  • Amino Acid Metabolism, Inborn Errors* / therapy
  • Argininosuccinic Aciduria*
  • Child, Preschool
  • Female
  • Humans
  • Hyperammonemia* / diagnosis
  • Hyperammonemia* / therapy
  • Infant
  • Male
  • Ornithine Carbamoyltransferase Deficiency Disease* / diagnosis
  • Ornithine Carbamoyltransferase Deficiency Disease* / therapy
  • Urea / metabolism*


  • Urea