SEMA4B

Chr 15

semaphorin 4B

Also known as: SEMAC, SemC

The protein inhibits axonal extension by providing local signals that specify territories inaccessible for growing axons, functioning as a guidance cue during neural development. Mutations cause autosomal recessive retinal dystrophy with early childhood onset, primarily affecting vision and retinal function. The gene shows relatively low constraint against loss-of-function variants (pLI = 0.0005, LOEUF = 0.533), consistent with its recessive inheritance pattern.

OMIMResearchSummary from RefSeq, UniProt
MultiplemechanismLOEUF 0.53
Clinical SummarySEMA4B
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

Moderate LoF intolerance
LoF Constraint
0.53LOEUF
pLI 0.001
Z-score 3.83
OE 0.34 (0.220.53)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
0.96Z-score
OE missense 0.88 (0.810.95)
430 obs / 489.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.34 (0.220.53)
00.351.4
Missense OE0.88 (0.810.95)
00.61.4
Synonymous OE1.11
01.21.6
LoF obs/exp: 13 / 38.8Missense obs/exp: 430 / 489.5Syn Z: -1.28
DN
0.6839th %ile
GOF
0.7028th %ile
LOF
0.2872th %ile

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

GOFprediction above median
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.

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

ClinVar Variant Classifications

0 submitted variants in ClinVar

Protein Context — Lollipop Plot

SEMA4B · 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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