CFB

Chr 6p21.33

complement factor B

Aliases:: H2-Bf
MANE:: ENST00000425368.7

OMIM: 138470 ↗NCBI: 629 ↗Ensembl ↗

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Predicted protein structure

AlphaFold predicted structure

CFB · P00751

v62025-08-01

Predicted Aligned Error matrix for CFB — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

86.3/ 100

Confident

764 residues

Confidence breakdown

Very high(≥ 90)64%
Confident(70–90)24%
Low(50–70)5%
Very low(< 50)7%

Open interactive 3D viewer

AlphaFold (Jumper et al., 2021) · CC BY 4.0

Clinical relevance (Genomics England PanelApp)

Diagnostic Grade (Green)

Atypical haemolytic uraemic syndrome
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
COVID-19 research
BOTH monoallelic and biallelic, autosomal or pseudoautosomal
Membranoproliferative glomerulonephritis including C3 glomerulopathy
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown
Unexplained kidney failure in young people
MONOALLELIC, autosomal or pseudoautosomal, NOT imprinted
Primary immunodeficiency or monogenic inflammatory bowel disease
BIALLELIC, autosomal or pseudoautosomal
Retinal disorders
MONOALLELIC, autosomal or pseudoautosomal, imprinted status unknown

Disease associations (Open Targets)

atypical hemolytic-uremic syndrome with B factor anomaly
0.76
atypical hemolytic-uremic syndrome
0.71
Immunodeficiency due to a complement cascade protein anomaly
0.61
complement 3 glomerulopathy
0.55
paroxysmal nocturnal hemoglobinuria
0.53
IgA glomerulonephritis
0.49
complement deficiency
0.42
hemolytic-uremic syndrome
0.37
primary membranoproliferative glomerulonephritis
0.37
membranoproliferative glomerulonephritis
0.37

Score is the Open Targets composite evidence score (0-1). Higher = stronger gene-disease association.

Protein function (UniProt)

Complement factor B

Precursor of the catalytic component of the C3 and C5 convertase complexes of the alternative pathway of the complement system, a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system (PubMed:3638964, PubMed:624565, PubMed:6554279, PubMed:6919543, PubMed:9748277). The alternative complement pathway acts as an amplification loop that enhances other complement pathways (classical, lectin and GZMK) by promoting formation of additional C3 and C5 convertases (PubMed:3638964, PubMed:624565, PubMed:6554279, PubMed:6919543, PubMed:9748277). CFB is cleaved and activated by CFD to generate Ba and Bb chains; Bb chain constituting the catalytic component of the C3 and C5 convertases (PubMed:6769474, PubMed:9748277)