Metabolic Brain Disease

, Volume 28, Issue 2, pp 269–275

Urea cycle defects and hyperammonemia: effects on functional imaging

  • Andrea L. Gropman
  • Morgan Prust
  • Andrew Breeden
  • Stanley Fricke
  • John VanMeter
Original Paper
  • 431 Downloads

Abstract

The urea-cycle disorders (UCDs) are a group of congenital enzyme and carrier deficiencies predisposing to hyperammonemia (HA). HA causes changes in the central nervous system (CNS) including alterations of neurotransmitter function, cell volume, and energy deprivation ultimately leading to cerebral edema. Neuropathological findings of UCDs primarily reflect changes in astrocyte morphology. Neurological features accompanying acute HA include changes in behavior and consciousness in the short term, and potential for impairments in memory and executive function as long-term effects. Plasma measures of ammonia and glutamine, although useful for clinical monitoring, prove poor markers of CNS function. Multimodal neuroimaging has potential to investigate impact on cognitive function by interrogating neural networks, connectivity and biochemistry. As neuroimaging methods become increasingly sophisticated, they will play a critical role in clinical monitoring and treatment of metabolic disease. We describe our findings in UCDs; with focus on Ornithine Transcarbamylase deficiency (OTCD) the only X linked UCD.

Keywords

Urea cycle disorders Brain MRI 

Copyright information

© Springer Science+Business Media New York 2012

Authors and Affiliations

  • Andrea L. Gropman
    • 1
    • 2
  • Morgan Prust
    • 1
    • 2
  • Andrew Breeden
    • 1
    • 2
  • Stanley Fricke
    • 1
    • 2
  • John VanMeter
    • 1
    • 2
  1. 1.Department of Neurology, Children’s National Medical CenterGeorge Washington University of the Health SciencesWashingtonUSA
  2. 2.Center for Functional and Molecular ImagingGeorgetown UniversityWashingtonUSA

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