GENE REFERENCE / HGNC:753

ASNS

asparagine synthetase (glutamine-hydrolyzing)

protein-coding gene7q21.3Gene information

What does this gene do?

The ASNS gene provides instructions for making an enzyme called asparagine synthetase. This enzyme is found in cells throughout the body, where it converts the protein building block (amino acid) aspartic acid to the amino acid asparagine. Another amino acid called glutamine helps in the conversion and is itself converted to the amino acid glutamic acid during the process. It is thought that asparagine synthetase helps to maintain the normal balance of these four amino acids in the body.

Asparagine is needed to produce many proteins but also plays other roles. Asparagine helps to break down toxic ammonia within cells, is important for protein modification, and is needed for making a certain molecule that transmits signals in the brain (a neurotransmitter).

Although asparagine can be obtained through the diet, the amino acid cannot cross the protective barrier that allows only certain substances to pass between blood vessels and the brain (the blood-brain barrier). As a result, brain cells rely solely on asparagine synthetase to produce asparagine.

Source: MedlinePlus, National Library of Medicine. Source publication: 2020-08-18. Source review: 2018-11.

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
congenital microcephaly - severe encephalopathy - progressive cerebral atrophy syndromeMONDO:0014258 · Evaluated 2020-06-29	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: 871
Submissions for variants in or overlapping this gene: 1,270
Submissions explicitly reporting this gene: 1,246
Alleles reported pathogenic / likely pathogenic: 191
VariationIDs with uncertain significance: 239
VariationIDs with conflicting classifications: 26

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 ASNS?

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 191 alleles in ASNS 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 ASNS.

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

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