FGB

Chr 4

fibrinogen beta chain

Also known as: HEL-S-78p

NCBI Gene: 2244ENSG00000171564UniProt: P02675

The fibrinogen beta chain is cleaved by thrombin to form fibrin monomers that polymerize into blood clots and plays essential roles in hemostasis, wound repair, and antimicrobial host defense. Mutations cause congenital afibrinogenemia, dysfibrinogenemia, and hypofibrinogenemia, presenting with bleeding disorders of variable severity. Inheritance is autosomal recessive for severe forms and autosomal dominant for milder variants.

ResearchSummary from RefSeq, OMIM, UniProt
LOEUF 0.43
Clinical Summary— FGB
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Gene-Disease Validity (ClinGen)
congenital fibrinogen deficiency · SDDefinitive

Definitive — sufficient evidence for diagnostic panels

⚡
Population Constraint (gnomAD)
Moderately constrained gene (pLI 0.57) — some intolerance to loss-of-function variants.
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ClinVar Variants
48 unique Pathogenic / Likely Pathogenic· 159 VUS of 297 total submissions
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Clinical Trials
1 active or recruiting trial — potential therapeutic options may be available
Explore recent and relevant literature in Research Assistant →
Some data sources returned errors (1)

omim: Error: OMIM fetch failed: 429

Population Genetics & Constraint

gnomAD v4 — loss-of-function & missense intolerance

gnomAD
Moderate LoF intolerance
LoF Constraint
0.43LOEUF
pLI 0.566
Z-score 3.63
OE 0.21 (0.11–0.43)
Moderately constrained

More LoF-intolerant than ~75% of genes

Missense Constraint
0.73Z-score
OE missense 0.87 (0.78–0.97)
231 obs / 264.5 exp
Tolerant

Mild missense constraint

Observed / Expected Ratios
LoF OE0.21 (0.11–0.43)
0≤0.351.4
Missense OE0.87 (0.78–0.97)
0≤0.61.4
Synonymous OE1.10
0≤1.21.6
LoF obs/exp: 5 / 24.3Missense obs/exp: 231 / 264.5Syn Z: -0.72

ClinVar Variant Classifications

297 submitted variants in ClinVar

ClinVar

Classification Summary

Pathogenic36
Likely Pathogenic12
VUS159
Likely Benign38
Benign38
Conflicting11
36
Pathogenic
12
Likely Pathogenic
159
VUS
38
Likely Benign
38
Benign
11
Conflicting

Curated Variants Distribution

Classified variants from ClinVar · 5 ACMG categories

ClassificationLoFMissense + InframeNon-codingSynonymousTotal
Pathogenic
4
5
27
0
36
Likely Pathogenic
5
3
4
0
12
VUS
5
112
40
2
159
Likely Benign
2
5
12
19
38
Benign
0
1
31
6
38
Conflicting
—11
Total1612611427294

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

View in ClinVar →

Protein Context — Lollipop Plot

FGB · 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 ↗
Key Publications
Landmark & review papers · by relevance
PubMed
Top 5 results · since 2015Search PubMed ↗
Recent Gene-Specific Literature
Gene in title · MEDLINE · newest first
Europe PMC
Congenital hypofibrinogenemia with bleeding risk: mutations in the FGA, FGB, and FGG genes.
Wu Y et al.·Lab Med
2026
Quantitative proteomic and glycoproteomic analysis identifies CLCA1, FBN1, and FGB as potential biomarkers for ulcerative colitis.
Wang X et al.·RSC Adv
2025Open Access
Bioinformatics analysis of the proteome in the pathway of complement and coagulation cascades in COVID-19: discovering potential biomarkers of FGB and SERPINA5.
Liu S et al.·BMC Infect Dis
2025Open Access
Recurrent Venous Thrombosis in a Hypofibrinogenemic Patient Despite a Heterozygous Deletion of the Fibrinogen Gene Cluster and Hemizygous FGB p.Pro265Leu Variant Mimicking a Homozygous Genotype.
Punniyamoorthy S et al.·Hamostaseologie
2025
A heterozygous nonsense mutation in the FGB gene (c.1299G > A) causes congenital fibrinogen disorder across four consecutive generations.
Chen W et al.·Thromb J
2025Open Access
Top 5 resultsSearch Europe PMC ↗

External Resources

Links to major genomics databases and tools

Franklin by Genoox
AI-powered variant curation and clinical analysis
DECIPHER
Genomic variants and phenotypes in rare disease patients