MAOA

Chr X

monoamine oxidase A

Also known as: BRNRS, MAO-A

NCBI Gene: 4128ENSG00000189221UniProt: P21397

This gene is one of two neighboring gene family members that encode mitochondrial enzymes which catalyze the oxidative deamination of amines, such as dopamine, norepinephrine, and serotonin. Mutation of this gene results in Brunner syndrome. This gene has also been associated with a variety of other psychiatric disorders, including antisocial behavior. Alternatively spliced transcript variants encoding multiple isoforms have been observed. [provided by RefSeq, Jul 2012]

GeneReviewsResearchGenerating clinical summary…

Primary Disease Associations & Inheritance

UniProtBrunner syndrome

Clinical highlights

Gene-disease validity (ClinGen)
Brunner syndrome · XLDefinitivesufficient evidence for diagnostic panels
Interpreting a novel variant
Loss of function is the curated mechanism (Gene2Phenotype) and the gene is intolerant of it in the population — truncating, frameshift and canonical splice variants carry more prior weight here than missense.Curated gene-level mechanism — a prior for triage, not a per-variant call.
3
Active trials
160
Pubs (1 yr)
—
P/LP submissions
—
P/LP missense
0.14
LOEUF· LoF intol.
LOF
Mechanism· G2P
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GeneReview available — MAOA
Authoritative clinical overview · Recommended first read
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Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
LoF intolerant — likely haploinsufficient
LoF Constraint?
0.14LOEUF
pLI 0.999
Z-score 4.24
OE 0.00 (0.00–0.14)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint?
2.38Z-score
OE missense 0.55 (0.47–0.64)
119 obs / 217.9 exp
Mild constraint

Moderately missense-constrained (top ~2.5%)

Observed / Expected Ratios?
LoF OE?0.00 (0.00–0.14)
0≤0.351.4
Missense OE?0.55 (0.47–0.64)
0≤0.61.4
Synonymous OE?0.83
0≤1.21.6
LoF obs/exp: 0 / 20.9Missense obs/exp: 119 / 217.9Syn Z: 1.22

ClinVar Variant Classifications

0 submitted variants in ClinVar

ClinVar

Protein Context — Lollipop Plot

MAOA · protein map & ClinVar variants

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

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients