The encoded protein forms an E3 ubiquitin ligase complex that catalyzes polyubiquitination of specific protein substrates and is required for proteolysis of DNA replication regulators including chromatin licensing and DNA replication factor 1 and cyclin E. Loss-of-function mutations cause X-linked syndromic intellectual developmental disorder, Cabezas type, with X-linked recessive inheritance. The gene is extremely intolerant to loss-of-function variation, consistent with its essential role in protein degradation pathways critical for DNA replication.

OMIMResearchSummary from RefSeq, OMIM, UniProt, Mechanism
LOFmechanismXLRLOEUF 0.091 OMIM phenotype
Clinical SummaryCUL4B
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Gene-Disease Validity (ClinGen)
X-linked intellectual disability, Cabezas type · 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 1.00). One damaged copy is likely sufficient to cause disease.
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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

Dual constrained — LoF & missense intolerant
LoF Constraint
0.09LOEUF
pLI 1.000
Z-score 5.48
OE 0.00 (0.000.09)
Highly constrained

Among the most LoF-intolerant genes (~top 3%)

Missense Constraint
3.77Z-score
OE missense 0.40 (0.350.47)
126 obs / 314.1 exp
Constrained

Highly missense-constrained (top ~0.1%)

Observed / Expected Ratios
LoF OE0.00 (0.000.09)
00.351.4
Missense OE0.40 (0.350.47)
00.61.4
Synonymous OE1.06
01.21.6
LoF obs/exp: 0 / 35.0Missense obs/exp: 126 / 314.1Syn Z: -0.52
Curated Mechanism (G2P)Gene2Phenotype (DDG2P) ↗
definitiveCUL4B-related syndromic intellectual developmental disorder, Cabezas typeLOFXLR
DN
0.3594th %ile
GOF
0.3590th %ile
LOF
0.80top 5%

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

LOFprediction above median · LOEUF 0.09

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

CUL4B · 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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