Research Article

Late onset N-acetylglutamate synthase deficiency caused by hypomorphic alleles†

  1. Ljubica Caldovic1,
  2. Hiroki Morizono1,
  3. Maria G. Panglao1,
  4. Giselle Y. Lopez3,
  5. Dashuang Shi1,
  6. Marshall L. Summar2,
  7. Mendel Tuchman1,*

Article first published online: 15 FEB 2005

DOI: 10.1002/humu.20146

Issue

Human Mutation

Human Mutation

Volume 25, Issue 3, pages 293–298, March 2005

Additional Information

How to Cite

Caldovic, L., Morizono, H., Panglao, M. G., Lopez, G. Y., Shi, D., Summar, M. L. and Tuchman, M. (2005), Late onset N-acetylglutamate synthase deficiency caused by hypomorphic alleles. Human Mutation, 25: 293–298. doi: 10.1002/humu.20146

Author Information

  1. 1

    Children's Research Institute, Children's National Medical Center, The George Washington University, Washington, DC

  2. 2

    Departments of Pediatrics and Molecular Physiology, Vanderbilt University Medical Center, Nashville, Tennessee

  3. 3

    College of Life Sciences; University of Maryland, College Park, Maryland

*Children's National Medical Center, 111 Michigan Ave. NW, Washington, DC 20010

  1. †

    Communicated by William S. Sly

Publication History

  1. Issue published online: 23 FEB 2005
  2. Article first published online: 15 FEB 2005
  3. Manuscript Accepted: 13 OCT 2004
  4. Manuscript Received: 26 JUL 2004

Funded by

  • National Institute of Diabetes Digestive and Kidney Diseases. Grant Numbers: R01DK47870, R01 DK064913
  • General Clinical Research Center Program of the National Center for Research Resources, National Institutes of Health, Department of Health and Human Services. Grant Number: M01-RR13297
  • Howard Hughes Medical Institute, Undergraduate Biological Sciences Education Program

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Keywords:

  • hyperammonemia;
  • mutation;
  • NAGS deficiency;
  • urea cycle

Abstract

N-acetylglutamate (NAG) is a unique cofactor that is essential for the conversion of ammonia to urea in the liver. N-acetylglutamate synthase (NAGS) catalyzes the formation of NAG. Deficiency of NAGS causes a block in ureagenesis resulting in hyperammonemia. Although a number of mutations have been identified in the NAGS gene, their effects on NAGS enzymatic activity have not been examined. We describe here three mutations in two families with NAGS deficiency. Studies of the purified recombinant mutant proteins revealed deleterious effects on NAGS affinity for substrates, and on the rate of catalysis. These studies provide a better understanding of the function of NAGS, and the mechanisms for deleterious effect of mutations causing inherited NAGS deficiency. Hum Mutat 25:293–298, 2005. © 2005 Wiley-Liss, Inc.

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