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ABAT

4-aminobutyrate aminotransferase

The ABAT gene provides instructions for producing the GABA-transaminase enzyme, which is crucial for breaking down the inhibitory neurotransmitter GABA in the brain. The ABAT gene is essential for proper brain function, encoding an enzyme responsible for GABA metabolism.

Chromosome 16p13.2 Various HGNC:23 Tier C
ABAT 16p13.2 p arm q arm 16

ABAT is located on the short (p) arm of chromosome 16, at band 16p13.2. Arm ratio per GRCh38 - banding schematic.

Explore chromosome 16 in the library →

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Clinical tests that include this

Carrier Screening panel
ABAT is 1 of 1,008 genes on this panel
Expanded carrier screening for recessive and X-linked conditions

Overview

The ABAT gene, also known as 4-aminobutyrate aminotransferase, plays a critical role in the human nervous system. It provides the genetic blueprint for an enzyme that metabolises gamma-aminobutyric acid (GABA), a key neurotransmitter. Maintaining appropriate GABA levels is vital for regulating brain cell activity and preventing overstimulation.

What the gene does

The ABAT gene instructs the production of GABA-transaminase, an enzyme responsible for breaking down the neurotransmitter GABA when it is no longer required. GABA acts as an inhibitory neurotransmitter, meaning it helps to slow down brain cell activity, preventing the brain from being overwhelmed by excessive signals. The proper functioning of the GABA-transaminase enzyme ensures that GABA levels are balanced, which is crucial for normal neurological processes and preventing conditions associated with GABA dysregulation.

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Chromosome location

The ABAT gene is situated on chromosome 16 at position 16p13.2. This specific location on the short arm of chromosome 16 helps to define its genomic address within the human genome.

Protein structure

The ABAT gene encodes a protein that is 500 amino acids in length. Domain architecture has not been experimentally characterised in detail for this protein.

Key variants

Genetic variations within the ABAT gene can affect the function of the GABA-transaminase enzyme. These variations range from single nucleotide changes to larger alterations, potentially leading to a dysfunctional or non-functional enzyme. Such changes can disrupt the delicate balance of GABA in the brain.

776
Total variants catalogued in ClinVar
View all on ClinVar →
39 Pathogenic / Likely pathogenic 309 Uncertain significance 395 Benign / Likely benign 33 Conflicting or other

Sample of pathogenic variants

10 pathogenic / likely-pathogenic variants from ClinVar, ranked by review status (expert-panel-reviewed first). This is a sample; recurrent founder variants in a specific population may not appear here - see the full ClinVar listing via the link above.

Variant (HGVS) Protein change Classification Evidence Associated condition
c.1128C>G
single nucleotide variant
 p.Tyr376Ter Pathogenic/Likely pathogenic ★★☆☆ Gamma-aminobutyric acid transaminase deficiency
c.168+1G>A
single nucleotide variant
 - Pathogenic ★★☆☆ Gamma-aminobutyric acid transaminase deficiency
c.22C>T
single nucleotide variant
 p.Gln8Ter Pathogenic/Likely pathogenic ★★☆☆ Gamma-aminobutyric acid transaminase deficiency
c.275G>A
single nucleotide variant
 p.Arg92Gln Pathogenic/Likely pathogenic ★★☆☆ Gamma-aminobutyric acid transaminase deficiency
c.631C>T
single nucleotide variant
 p.Leu211Phe Pathogenic/Likely pathogenic ★★☆☆ Inborn genetic diseases
g.(?_8768473)_(8878428_?)del
Deletion
 - Pathogenic ★☆☆☆ Gamma-aminobutyric acid transaminase deficiency
c.1031G>A
single nucleotide variant
 p.Trp344Ter Pathogenic ★☆☆☆ Gamma-aminobutyric acid transaminase deficiency
c.1145G>A
single nucleotide variant
 p.Trp382Ter Pathogenic ★☆☆☆ Gamma-aminobutyric acid transaminase deficiency
c.1393G>C
single nucleotide variant
 p.Gly465Arg Pathogenic ★☆☆☆ Gamma-aminobutyric acid transaminase deficiency
c.1433T>C
single nucleotide variant
 p.Leu478Pro Pathogenic ★☆☆☆ Gamma-aminobutyric acid transaminase deficiency

Evidence stars indicate ClinVar review status. Individual variant interpretation should always be performed by a qualified clinical laboratory - many variants remain classified as Variants of Uncertain Significance (VUS) pending more research.

Associated conditions

Pathogenic variants in the ABAT gene are associated with GABA-transaminase deficiency, a severe neurological disorder that typically manifests in infancy. This condition is characterised by recurrent seizures, significant developmental delay, movement difficulties, and accelerated linear growth despite feeding challenges.

No disease links recorded for this gene in our reference set.

UK clinical status

The ABAT gene is included in several UK NHS national genomic testing panels, indicating its clinical significance within the UK healthcare system. It is listed as 'green' in panels related to Dystonia, chorea or related movement disorder (childhood onset), Early onset or syndromic epilepsy, Intellectual disability, Likely inborn error of metabolism, Mitochondrial disorders, Mitochondrial DNA maintenance disorder, Possible mitochondrial disorder (nuclear genes), and Undiagnosed metabolic disorders.

Green-listed
High evidence · clinically actionable in NHS testing
Included in NHS GMS signed-off panels
Dystonia, chorea or related movement disorder, childhood onset · R57 NHS GMS → Likely inborn error of metabolism · R98 NHS GMS → Mitochondrial DNA maintenance disorder · R352 NHS GMS → Possible mitochondrial disorder, nuclear genes · R63 NHS GMS → DDG2P NHS GMS → Early onset or syndromic epilepsy NHS GMS → Intellectual disability NHS GMS → Mitochondrial disorders NHS GMS →
NHS Genomic Medicine Service Jeen carrier screening

Sources: NHS GMS PanelApp · Genomics England PanelApp · NHS National Genomic Test Directory

Frequently asked questions

What is the main function of the ABAT gene?

The ABAT gene provides instructions for making the GABA-transaminase enzyme, which is crucial for breaking down the neurotransmitter GABA in the brain. This process helps regulate brain cell activity.

What is GABA-transaminase deficiency?

GABA-transaminase deficiency is a brain disorder caused by mutations in the ABAT gene. It typically starts in infancy and is characterised by severe seizures, developmental delay, and movement problems due to impaired GABA metabolism.

How is the ABAT gene relevant to neurological health?

The ABAT gene's role in metabolising GABA directly impacts neurological health. Imbalances in GABA levels, often caused by ABAT gene variants, can lead to severe conditions affecting brain function and development.

References

  1. Nagappa M, Bindu PS, Chiplunkar S. Hypersomnolence-hyperkinetic movement disorder in a child with compound heterozygous mutation in 4-aminobutyrate aminotransferase (ABAT) gene. Brain & development. 2017. PMID: 27596361
  2. Koenig MK, Hodgeman R, Riviello JJ. Phenotype of GABA-transaminase deficiency. Neurology. 2017. PMID: 28411234
  3. Louro P, Ramos L, Robalo C. Phenotyping GABA transaminase deficiency: a case description and literature review. Journal of inherited metabolic disease. 2016. PMID: 27376954
  4. Besse A, Petersen AK, Hunter JV. Personalized medicine approach confirms a milder case of ABAT deficiency. Molecular brain. 2016. PMID: 27903293
  5. Tsuji M, Aida N, Obata T. A new case of GABA transaminase deficiency facilitated by proton MR spectroscopy. Journal of inherited metabolic disease. 2010. PMID: 20052547
  6. Pearl PL, Gibson KM. Clinical aspects of the disorders of GABA metabolism in children. Current opinion in neurology. 2004. PMID: 15021235
  7. Medina-Kauwe LK, Tobin AJ, De Meirleir L. 4-Aminobutyrate aminotransferase (GABA-transaminase) deficiency. Journal of inherited metabolic disease. 1999. PMID: 10407778
Educational content. This page is not medical or genetic advice, is not individually reviewed by a clinician for each reader, and should not replace a consultation with a qualified healthcare professional or genetic counsellor. If you are considering genetic testing or acting on a test result, book a consultation.
Data sources Last updated 4 October 2026. Content compiled from HGNC · MedlinePlus Genetics · ClinGen · Genomics England PanelApp · NHS National Genomic Test Directory · ClinVar · UniProt · AlphaFold .