FBXL4

Chr 6AR

F-box and leucine rich repeat protein 4

Also known as: FBL4, FBL5, MTDPS13

The protein functions as part of an E3 ubiquitin ligase complex that regulates protein degradation, including control of lysine-specific demethylase 4A levels in cell-cycle regulation. Biallelic mutations cause mitochondrial DNA depletion syndrome 13 (encephalomyopathic type), inherited in an autosomal recessive pattern. The pathogenic mechanism involves disrupted mitochondrial DNA maintenance leading to mitochondrial dysfunction and subsequent encephalomyopathy.

OMIMResearchSummary from RefSeq, OMIM, UniProt
LOFmechanismARLOEUF 0.921 OMIM phenotype
Clinical SummaryFBXL4
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Gene-Disease Validity (ClinGen)
Leigh syndrome · ARDefinitive

Definitive — sufficient evidence for diagnostic panels

2 total gene-disease associations curated

Population Constraint (gnomAD)
Low constraint (pLI 0.00) — loss-of-function variants are relatively tolerated in the population.
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ClinVar Variants
43 unique Pathogenic / Likely Pathogenic· 11 VUS of 73 total submissions
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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

Tolerant — LoF & missense variants common in population
LoF Constraint
0.92LOEUF
pLI 0.000
Z-score 1.90
OE 0.61 (0.420.92)
Tolerant

Typical tolerance to LoF variation

Missense Constraint
0.55Z-score
OE missense 0.91 (0.831.01)
299 obs / 327.2 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.61 (0.420.92)
00.351.4
Missense OE0.91 (0.831.01)
00.61.4
Synonymous OE1.01
01.21.6
LoF obs/exp: 17 / 27.8Missense obs/exp: 299 / 327.2Syn Z: -0.10

ClinVar Variant Classifications

73 submitted variants in ClinVar

Classification Summary

Pathogenic20
Likely Pathogenic23
VUS11
Likely Benign3
Benign5
Conflicting11
20
Pathogenic
23
Likely Pathogenic
11
VUS
3
Likely Benign
5
Benign
11
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
15
0
4
1
20
Likely Pathogenic
4
18
1
0
23
VUS
0
6
3
2
11
Likely Benign
0
0
1
2
3
Benign
0
1
1
3
5
Conflicting
11
Total192510873

LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly

View in ClinVar →

Protein Context — Lollipop Plot

FBXL4 · protein map & ClinVar variants

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

3D Protein StructureAlphaFold
Clinical Literature
Open Research Assistant →
Full-Text Mentions
NLP-detected gene mentions in article bodies · via PubTator3
PubTator3
Top 5 full-text resultsSearch PubTator3 ↗