PAK1

Chr 11AD

p21 (RAC1) activated kinase 1

Also known as: IDDMSSD, PAKalpha, alpha-PAK, p65-PAK

This gene encodes a serine/threonine protein kinase that regulates cytoskeleton dynamics, cell adhesion, migration, and synaptic function by linking Rho GTPases to downstream signaling pathways. Mutations cause autosomal dominant intellectual developmental disorder with macrocephaly, seizures, and speech delay. The gene shows tolerance to loss-of-function variants (pLI 0.001, LOEUF 0.563), suggesting the pathogenic variants may act through other mechanisms.

OMIMResearchSummary from RefSeq, OMIM, UniProt
GOFmechanismADLOEUF 0.561 OMIM phenotype
Clinical SummaryPAK1
Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.34) despite low pLI — interpret in context.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Missense constrained — critical functional residues
LoF Constraint
0.56LOEUF
pLI 0.001
Z-score 3.48
OE 0.34 (0.210.56)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
4.00Z-score
OE missense 0.36 (0.310.42)
113 obs / 312.0 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.34 (0.210.56)
00.351.4
Missense OE0.36 (0.310.42)
00.61.4
Synonymous OE0.97
01.21.6
LoF obs/exp: 11 / 32.4Missense obs/exp: 113 / 312.0Syn Z: 0.24
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
strongPAK1-related neurodevelopmental disorderGOFAD
DN
0.80top 25%
GOF
0.78top 25%
LOF
0.2970th %ile

This gene has evidence for multiple mechanisms of pathogenicity (dominant-negative and gain-of-function). Both the Badonyi & Marsh prediction and the broader genomic evidence point to dominant-negative as the predominant mechanism. Different variants in this gene may act through different mechanisms — interpret in context of the specific variant.

DNprediction above median · 1 literature citation
GOFprediction above median · 1 literature citation

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

DNFurthermore, sublethal doses of IPA3 or ectopic expression of dominant-negative PAK1 sensitized Ras-mutated cells to GDC-0897 and AZD6244, which otherwise have reduced efficiency against cells with activated Ras.PMID:22869096
GOFActivating Mutations in PAK1, Encoding p21-Activated Kinase 1, Cause a Neurodevelopmental DisorderPMID:30290153

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

PAK1 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold

Clinical Trials

Active and recruiting trials from ClinicalTrials.gov

No active trials found for this gene.

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Clinical Literature
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Full-Text Mentions
NLP-detected gene mentions in article bodies · via PubTator3
PubTator3
Top 5 full-text resultsSearch PubTator3 ↗