FBXL2
Chr 3F-box and leucine rich repeat protein 2
Also known as: FBL2, FBL3
The protein functions as a calcium-activated substrate recognition component of the SCF ubiquitin ligase complex, targeting specific proteins including cyclins and inflammatory regulators for degradation to control cell cycle progression, autophagy, and inflammation. Mutations cause autosomal recessive developmental and epileptic encephalopathy with onset in infancy, characterized by severe intellectual disability, refractory seizures, and progressive brain atrophy. The gene shows moderate constraint against loss-of-function variants (LOEUF 0.52), consistent with its role in essential cellular processes.
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
More LoF-intolerant than ~75% of genes
Moderately missense-constrained (top ~2.5%)
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.
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
119 submitted variants in ClinVar
Classification Summary
Curated Variants Distribution
Classified variants from ClinVar · 5 ACMG categories
| Classification | LoF | Missense + Inframe | Non-coding | Synonymous | Total |
|---|---|---|---|---|---|
Pathogenic | 0 | 0 | 17 | 0 | 17 |
Likely Pathogenic | 0 | 0 | 0 | 0 | 0 |
VUS | 0 | 70 | 2 | 0 | 72 |
Likely Benign | 0 | 4 | 0 | 1 | 5 |
Benign | 0 | 0 | 0 | 0 | 0 |
| Total | 0 | 74 | 19 | 1 | 94 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
FBXL2 · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
3D Protein StructureAlphaFold
External Resources
Links to major genomics databases and tools
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
No active trials found for this gene.
Search ClinicalTrials.gov →External Resources
Links to major genomics databases and tools