Brunner syndrome: genes and variants
Brunner syndrome is linked to 1 analyzed protein (MAOA). 2 DNA variants are known to cause it; 50 more are uncertain, and 0 of those already look disease-causing on computable evidence.
Last updated 2026-09-30. Research information, not medical advice.
Genes linked to Brunner syndrome
MAOA: Amine oxidase [flavin-containing] A
It degrades serotonin, norepinephrine, dopamine, and other monoamines at the outer mitochondrial membrane and therefore strongly influences neurotransmitter turnover. Rare loss-of-function variants can cause Brunner syndrome with impulsive behavior and neurodevelopmental abnormalities, while enzyme inhibition is used therapeutically in depression.
2 disease-causing and 50 uncertain variants in MAOA are linked to Brunner syndrome.
Known disease-causing variants in Brunner syndrome
| Variant | Position | Protein part | Clinical label |
|---|---|---|---|
| MAOA R45W | 45 | Cytoplasmic | Disease-causing (★★) |
| MAOA V244I | 244 | Cytoplasmic | Disease-causing (★) |
Frequently asked questions
Which genes are linked to Brunner syndrome?
In CATVariant, Brunner syndrome is linked to 1 analyzed protein: MAOA (Amine oxidase [flavin-containing] A).
How many genetic variants are linked to Brunner syndrome?
61 variants: 2 are classified as disease-causing (pathogenic or likely pathogenic) in ClinVar and 50 are of uncertain significance or have conflicting reports.
Which uncertain variants in Brunner syndrome look disease-causing?
None of the uncertain variants currently reaches the likely-pathogenic range on computable evidence alone.
About this data
Variant–disease links come from ClinVar, Open Targets and UniProt, pooled from the latest public CATVariant analysis of each human protein. Evidence scores use the ACMG/AMP Bayesian points scale with computable criteria only (position among known disease variants, rarity in gnomAD, calibrated predictors, deep mutational scanning); there is no family or patient data, so they prioritise variants for expert review and never classify them.
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