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Recurrent Encephalopathy: NAGS (N-Acetylglutamate Synthase) Deficiency in Adults

Published online by Cambridge University Press:  23 September 2014

A. Cartagena
Affiliation:
Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada
A.N. Prasad
Affiliation:
Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada Paediatrics, University of Western Ontario, London, Ontario, Canada Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada
C.A. Rupar
Affiliation:
Biochemistry, University of Western Ontario, London, Ontario, Canada
M. Strong
Affiliation:
Department of Clinical Neurological Sciences, University of Western Ontario, London, Ontario, Canada
M. Tuchman
Affiliation:
Center for Genetic Medicine Research, Children's Research Institute, Children's National Medical Center, Washington DC, USA
N. Ah Mew
Affiliation:
Center for Clinical an Community Research, Children's Research Institute, Children's National Medical Center, Washington DC, USA
C. Prasad*
Affiliation:
Paediatrics, University of Western Ontario, London, Ontario, Canada Children's Health Research Institute, University of Western Ontario, London, Ontario, Canada
*
Children's Hospital, London Health Sciences Centre, 800 Commissioners Road East, London, Ontario, N6C 2V5, Canada, Email: Chitra.Prasad@lhsc.on.ca
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Abstract:

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N-acetyl-glutamate synthase (NAGS) deficiency is a rare autosomal recessive urea cycle disorder (UCD) that uncommonly presents in adulthood. Adult presentations of UCDs include; confusional episodes, neuropsychiatric symptoms and encephalopathy. To date, there have been no detailed neurological descriptions of an adult onset presentation of NAGS deficiency. In this review we examine the clinical presentation and management of UCDs with an emphasis on NAGS deficiency. An illustrative case is provided. Plasma ammonia levels should be measured in all adult patients with unexplained encephalopathy, as treatment can be potentially life-saving. Availability of N-carbamylglutamate (NCG; carglumic acid) has made protein restriction largely unnecessary in treatment regimens currently employed. Genetic counselling remains an essential component of management of NAGS.

Type
Review Article
Copyright
Copyright © The Canadian Journal of Neurological 2013

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