RAC3 encodes a plasma membrane-associated small GTPase that regulates cellular processes including cell spreading, formation of actin-based protrusions, and cell adhesion through cycling between active GTP-bound and inactive GDP-bound states. Mutations cause autosomal dominant neurodevelopmental disorder with structural brain anomalies and dysmorphic facies. The gene shows tolerance to loss-of-function variants (pLI 0.003, LOEUF 1.27), suggesting the pathogenic variants may work through alternative mechanisms.

OMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismADLOEUF 1.271 OMIM phenotype
Clinical SummaryRAC3
Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Tolerant — LoF & missense variants common in population
LoF Constraint
1.27LOEUF
pLI 0.003
Z-score 1.06
OE 0.60 (0.311.27)
Tolerant

Highly tolerant — LoF variants common in population

Missense Constraint
1.46Z-score
OE missense 0.63 (0.520.76)
78 obs / 123.8 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.60 (0.311.27)
00.351.4
Missense OE0.63 (0.520.76)
00.61.4
Synonymous OE1.69
01.21.6
LoF obs/exp: 5 / 8.3Missense obs/exp: 78 / 123.8Syn Z: -4.09
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
strongRAC3-related neurodevelopment disorderOTHERAD
DN
0.81top 10%
GOF
0.75top 25%
LOF
0.3161th %ile

This gene has evidence for multiple mechanisms of pathogenicity (gain-of-function and dominant-negative). The Badonyi & Marsh model scores dominant-negative highest among its predictions, but genomic evidence (constraint, ClinVar variant spectrum, and literature) most strongly supports gain-of-function. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

GOFprediction above median · 1 literature citation
DNprediction above median

Note: In-silico variant effect predictors (SIFT, PolyPhen, REVEL, CADD) may underestimate pathogenicity of missense variants in genes with GOF or DN mechanisms. Consider functional evidence and clinical context.

Literature Evidence

GOFThe specific nucleotide substitution c.86C>T leading to p.(Pro29Leu) was shown in the C. elegans ortholog of RAC3 to result in aberrant axon guidance via an apparent gain-of-function mechanism.PMID:30293988

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

RAC3 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold
Clinical Literature
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