MAOA
Chr XXLRmonoamine oxidase A
Also known as: BRNRS, MAO-A
This mitochondrial enzyme catalyzes the oxidative deamination of neurotransmitters including serotonin, dopamine, and norepinephrine. Mutations cause Brunner syndrome, an X-linked recessive disorder characterized by intellectual disability and behavioral abnormalities. The gene is highly constrained against loss-of-function variants, indicating that complete loss of enzyme activity has severe consequences.
Primary Disease Associations & Inheritance
Definitive — sufficient evidence for diagnostic panels
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
Among the most LoF-intolerant genes (~top 3%)
Moderately missense-constrained (top ~2.5%)
ClinVar Variant Classifications
100 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 1 | 0 | 1 |
Likely Pathogenic | 0 | 0 | 0 | 0 | 0 |
VUS | 0 | 9 | 3 | 0 | 12 |
Likely Benign | 0 | 1 | 2 | 0 | 3 |
Benign | 0 | 0 | 0 | 0 | 0 |
| Total | 0 | 10 | 6 | 0 | 16 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in 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.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
Online Study of People Who Have Genetic Changes and Features of Autism: Simons Searchlight
RECRUITINGGenetic and Clinical Correlates of Disruptive Behavior Disorder With and Without Callous-Unemotional Traits
ACTIVE NOT RECRUITINGExternal Resources
Links to major genomics databases and tools