PAK3

Chr XXLR

p21 (RAC1) activated kinase 3

Also known as: ARA, MRX30, MRX47, OPHN3, PAK-3, PAK3beta, XLID30, bPAK

PAK3 encodes a serine/threonine kinase that regulates cytoskeletal reorganization, dendritic spine morphogenesis, and synaptic plasticity by acting downstream of CDC42 and RAC1. Mutations cause X-linked intellectual developmental disorder with inheritance following an X-linked recessive pattern. The gene is highly constrained against loss-of-function variants, indicating that complete loss of protein function is likely not tolerated.

OMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismXLRLOEUF 0.291 OMIM phenotype
Clinical SummaryPAK3
🧬
Gene-Disease Validity (ClinGen)
X-linked syndromic intellectual disability · XLDefinitive

Definitive — sufficient evidence for diagnostic panels

Population Constraint (gnomAD)
Highly constrained gene — heterozygous loss-of-function variants are very rare in the population (pLI 0.99). One damaged copy is likely sufficient to cause disease.
💊
Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Dual constrained — LoF & missense intolerant
LoF Constraint
0.29LOEUF
pLI 0.987
Z-score 3.95
OE 0.09 (0.040.29)
Highly constrained

Highly LoF-intolerant (top ~10% of genes)

Missense Constraint
3.53Z-score
OE missense 0.32 (0.260.39)
69 obs / 214.7 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.09 (0.040.29)
00.351.4
Missense OE0.32 (0.260.39)
00.61.4
Synonymous OE0.95
01.21.6
LoF obs/exp: 2 / 22.0Missense obs/exp: 69 / 214.7Syn Z: 0.32
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitivePAK3-related intellectual developmental disorderLOFXLR
definitivePAK3-related agenesis of the corpus callosumGOFXLR
DN
0.4884th %ile
GOF
0.6248th %ile
LOF
0.65top 25%

The highest-scoring mechanism for this gene is loss-of-function (haploinsufficiency).

LOFprediction above median · LOEUF 0.29

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.

Predictions from Badonyi M, Marsh JA. PLoS ONE. 2024;19(8):e0307312. Mechanism ranking also informed by gnomAD constraint, ClinVar, and ClinGen data.

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

PAK3 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold
Clinical Literature
Open Research Assistant →