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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed October 2006

What is the official name of the NAGS gene?

The official name of this gene is “N-acetylglutamate synthase.”

NAGS is the gene's official symbol. The NAGS gene is also known by other names, listed below.

What is the normal function of the NAGS gene?

The NAGS gene provides instructions for making the enzyme N-acetylglutamate synthase. This enzyme is needed for the urea cycle, a series of reactions that occurs in liver cells. The urea cycle processes excess nitrogen, generated when protein is used by the body, into a compound called urea that is excreted by the kidneys. Excreting the excess nitrogen prevents it from accumulating in the form of ammonia, which is toxic, especially to the nervous system.

N-acetylglutamate synthase controls the production of a compound called N-acetylglutamate in the mitochondria, the energy-producing centers in cells. N-acetylglutamate is necessary to activate the enzyme carbamoyl phosphate synthetase I. This enzyme controls the first step of the urea cycle, in which excess nitrogen compounds are incorporated into the cycle to be processed.

How are changes in the NAGS gene related to health conditions?

N-acetylglutamate synthase deficiency - caused by mutations in the NAGS gene

Approximately 12 NAGS gene mutations have been identified in people with N-acetylglutamate synthase deficiency. A mutated NAGS gene may result in an N-acetylglutamate synthase enzyme that is shorter than normal or the wrong shape, or may prevent the enzyme from being produced at all.

The shape of an enzyme affects its ability to control a chemical reaction. If the N-acetylglutamate synthase enzyme is damaged or missing, N-acetylglutamate will be produced in lower-than-normal amounts, or not at all. This shortage of N-acetylglutamate interferes with proper activation of carbamoyl phosphate synthetase I, preventing it from fulfilling its role in the urea cycle. Excess nitrogen is not converted to urea for excretion, and ammonia accumulates in the body. This accumulation causes neurological problems and other signs and symptoms of N-acetylglutamate synthase deficiency.

Where is the NAGS gene located?

Cytogenetic Location: 17q21.31

Molecular Location on chromosome 17: base pairs 44,004,546 to 44,009,068

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The NAGS gene is located on the long (q) arm of chromosome 17 at position 21.31.

The NAGS gene is located on the long (q) arm of chromosome 17 at position 21.31.

More precisely, the NAGS gene is located from base pair 44,004,546 to base pair 44,009,068 on chromosome 17.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about NAGS?

You and your healthcare professional may find the following resources about NAGS helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the NAGS gene or gene products?

  • AGAS
  • ARGA
  • MGC133025
  • NAT7

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding NAGS?

ammonia ; compound ; deficiency ; enzyme ; excretion ; gene ; mitochondria ; nervous system ; neurological ; phosphate ; protein ; toxic ; urea

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Caldovic L, Morizono H, Gracia Panglao M, Gallegos R, Yu X, Shi D, Malamy MH, Allewell NM, Tuchman M. Cloning and expression of the human N-acetylglutamate synthase gene. Biochem Biophys Res Commun. 2002 Dec 13;299(4):581-6. (
  • Caldovic L, Morizono H, Panglao MG, Cheng SF, Packman S, Tuchman M. Null mutations in the N-acetylglutamate synthase gene associated with acute neonatal disease and hyperammonemia. Hum Genet. 2003 Apr;112(4):364-8. Epub 2003 Feb 20. (
  • Caldovic L, Morizono H, Panglao MG, Lopez GY, Shi D, Summar ML, Tuchman M. Late onset N-acetylglutamate synthase deficiency caused by hypomorphic alleles. Hum Mutat. 2005 Mar;25(3):293-8. (
  • Caldovic L, Tuchman M. N-acetylglutamate and its changing role through evolution. Biochem J. 2003 Jun 1;372(Pt 2):279-90. Review. (
  • Häberle J, Schmidt E, Pauli S, Kreuder JG, Plecko B, Galler A, Wermuth B, Harms E, Koch HG. Mutation analysis in patients with N-acetylglutamate synthase deficiency. Hum Mutat. 2003 Jun;21(6):593-7. (
  • Morizono H, Caldovic L, Shi D, Tuchman M. Mammalian N-acetylglutamate synthase. Mol Genet Metab. 2004 Apr;81 Suppl 1:S4-11. Review. (
  • NCBI Gene (
  • Schmidt E, Nuoffer JM, Häberle J, Pauli S, Guffon N, Vianey-Saban C, Wermuth B, Koch HG. Identification of novel mutations of the human N-acetylglutamate synthase gene and their functional investigation by expression studies. Biochim Biophys Acta. 2005 Apr 15;1740(1):54-9. Epub 2005 Feb 24. (


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? ( in the Handbook.

Reviewed: October 2006
Published: February 8, 2016