GENE REFERENCE / HGNC:17996

NAGS

N-acetylglutamate synthase

protein-coding gene17q21.31Gene information

What does this gene do?

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 breaks down excess nitrogen, which is made when protein is used by the body, into a compound called urea. Urea is removed from the body in urine. Removing the excess nitrogen prevents it from accumulating in the form of ammonia, which is toxic at high levels, especially to the brain.

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 turn on 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 broken down.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2019-07.

ClinGen reviews

ClinGen reviews the evidence linking a particular gene to a condition. Each rating below describes the strength of that link. It does not classify a variant in your DNA file.

Condition	Inheritance	Evidence
hyperammonemia due to N-acetylglutamate synthase deficiencyMONDO:0009377 · Evaluated 2019-07-26	Autosomal recessive	DefinitiveAminoacidopathy Gene Curation Expert Panel

ClinVar records

These numbers show what has been submitted to ClinVar. They cannot tell you how likely you are to have a condition.

Submitted alleles: 717
Submissions for variants in or overlapping this gene: 986
Submissions explicitly reporting this gene: 973
Alleles reported pathogenic / likely pathogenic: 115
VariationIDs with uncertain significance: 177
VariationIDs with conflicting classifications: 21

The rows count different things: alleles, submissions or VariationIDs. Their categories can overlap, so do not add them together. Pathogenic/likely pathogenic counts exclude structural variants that merely overlap a gene. A dash in the source means “not reported,” not zero.

NCBI produces the gene-summary file each week using counts recorded at the start of the month. The numbers may differ from those on the live ClinVar website. Read the field definitions ↗

View this gene in ClinVar ↗

YOUR DNA FILE

Can your DNA file tell you about NAGS?

From a DNA test kit (such as 23andMe, AncestryDNA or MyHeritage). These kits check a fixed list of about 600,000 to 700,000 positions across your whole genome. ClinVar lists 115 alleles in NAGS reported as pathogenic or likely pathogenic. A kit checks only some of these positions, and often none of them.

From whole genome sequencing (a VCF file). Sequencing reads most of your genome. Your file lists the places where your DNA differs from the reference genome. Some regions are hard to sequence, including parts of some genes that have near-identical copies elsewhere, and a VCF file does not record which positions were read well.

If a variant is not in your file, that does not mean you don’t have it.

What BioDecode checks

BioDecode compares every variant in your file with ClinVar, on your own computer. For each match, it shows the ClinVar classification, the review status and the condition it was reported for. Your file is not uploaded.

A ClinVar classification applies to one particular variant and the condition it was reported for. It does not tell you about other variants in NAGS.

BioDecode cannot fill gaps in your test, diagnose a condition or replace clinical testing.

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