ABAT

Chr 16AR

4-aminobutyrate aminotransferase

Also known as: GABA-AT, GABAT, NPD009

4-aminobutyrate aminotransferase catalyzes the breakdown of GABA, the brain's primary inhibitory neurotransmitter, into succinate semialdehyde. Mutations cause GABA-transaminase deficiency, an autosomal recessive disorder characterized by early-onset psychomotor retardation, hypotonia, hyperreflexia, lethargy, and refractory seizures with EEG abnormalities. The gene shows moderate intolerance to loss-of-function variants (LOEUF 0.567).

GeneReviewsOMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismARLOEUF 0.571 OMIM phenotype
Clinical SummaryABAT
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Gene-Disease Validity (ClinGen)
developmental and epileptic encephalopathy · ARModerate

Moderate evidence — consider for supplementary testing

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.32) despite low pLI — interpret in context.
📋
ClinVar Variants
8 unique Pathogenic / Likely Pathogenic· 40 VUS of 200 total submissions
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GeneReview available — ABAT
Authoritative clinical overview · Recommended first read
Open GeneReview ↗

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Moderate LoF intolerance
LoF Constraint
0.57LOEUF
pLI 0.006
Z-score 3.29
OE 0.32 (0.200.57)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
0.57Z-score
OE missense 0.91 (0.821.00)
266 obs / 293.6 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.32 (0.200.57)
00.351.4
Missense OE0.91 (0.821.00)
00.61.4
Synonymous OE1.08
01.21.6
LoF obs/exp: 9 / 27.7Missense obs/exp: 266 / 293.6Syn Z: -0.64
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveABAT-related GABA-transaminase deficiencyLOFAR

Predictions shown for reference only — model trained on dominant genes, not applicable to AR conditions.

DN
0.75top 25%
GOF
0.5759th %ile
LOF
0.3065th %ile

The Badonyi & Marsh prediction model was trained exclusively on dominant disease genes. Predictions are not reliable for genes with autosomal recessive inheritance and are shown at reduced opacity for reference only.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312.

ClinVar Variant Classifications

200 submitted variants in ClinVar

Classification Summary

Pathogenic5
Likely Pathogenic3
VUS40
Likely Benign127
Benign2
5
Pathogenic
3
Likely Pathogenic
40
VUS
127
Likely Benign
2
Benign

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
4
0
1
0
5
Likely Pathogenic
1
0
2
0
3
VUS
0
36
4
0
40
Likely Benign
2
3
72
50
127
Benign
0
0
1
1
2
Total7398051177

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

ABAT · protein map & ClinVar variants

Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

Search ClinicalTrials.gov →
Clinical Literature
Open Research Assistant →
Full-Text Mentions
NLP-detected gene mentions in article bodies · via PubTator3
PubTator3
Top 5 full-text resultsSearch PubTator3 ↗