The encoded phospholipase C beta 4 enzyme catalyzes the formation of inositol 1,4,5-trisphosphate and diacylglycerol from phosphatidylinositol 4,5-bisphosphate, serving as a direct effector in endothelin receptor signaling pathways essential for lower jaw and middle ear development. Mutations cause auriculocondylar syndrome 2A and 2B, craniofacial malformation disorders affecting jaw and ear structures. The gene shows both autosomal dominant and autosomal recessive inheritance patterns and is highly constrained against loss-of-function variants.

OMIMResearchSummary from RefSeq, OMIM, UniProt
MultiplemechanismAD/ARLOEUF 0.452 OMIM phenotypes
Clinical SummaryPLCB4
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Gene-Disease Validity (ClinGen)
auriculocondylar syndrome 2 · ADDefinitive

Definitive — sufficient evidence for diagnostic panels

2 total gene-disease associations curated

Population Constraint (gnomAD)
Constrained for loss-of-function variants (OE-LoF 0.32) despite low pLI — interpret in context.

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

Missense constrained — critical functional residues
LoF Constraint
0.45LOEUF
pLI 0.000
Z-score 5.55
OE 0.32 (0.230.45)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
3.57Z-score
OE missense 0.60 (0.550.65)
382 obs / 635.4 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.32 (0.230.45)
00.351.4
Missense OE0.60 (0.550.65)
00.61.4
Synonymous OE0.99
01.21.6
LoF obs/exp: 25 / 77.8Missense obs/exp: 382 / 635.4Syn Z: 0.13
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
strongPLCB4-related auriculocondylar syndromeOTHERAD
DN
0.6261th %ile
GOF
0.6052th %ile
LOF
0.3453th %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
GOF1 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

DNRecently, phospholipase C, b 4 (PLCB4) mutations were identified as the major cause of autosomal dominant ACS, with mutations of the PLCB4 catalytic domain predicted to have a dominant negative effect.PMID:23913798
GOFTaken together these data suggest that the PLCB4 hotspot mutation is similarly a gain-of-function mutation leading to activation of the same signaling pathway, promoting UM tumorigenesis.PMID:26683228

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

PLCB4 · 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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