C4B

Chr 6p21.33

complement C4B (Chido/Rodgers blood group)

Aliases:: CPAMD3, C4F, CO4, C4B1, C4B3
MANE:: ENST00000435363.7

OMIM: 120820 ↗NCBI: 721 ↗Ensembl ↗

Annotations refreshed 1 month ago.

Predicted protein structure

AlphaFold predicted structure

C4B · P0C0L5

v62025-08-01

Predicted Aligned Error matrix for C4B — diagonal shows residue index, colour shows pairwise prediction confidence (lower is better) — Predicted Aligned Error

Mean pLDDT

83.4/ 100

Confident

1,744 residues

Confidence breakdown

Very high(≥ 90)42%
Confident(70–90)45%
Low(50–70)6%
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)

COVID-19 research
BIALLELIC, autosomal or pseudoautosomal
Primary immunodeficiency or monogenic inflammatory bowel disease
BIALLELIC, autosomal or pseudoautosomal

Disease associations (Open Targets)

immunodeficiency due to a classical component pathway complement deficiency
0.62
complement deficiency
0.46
systemic lupus erythematosus
0.39
dengue disease
0.38
neoplasm
0.10
cancer
0.09
coronary artery disorder
0.08
cyclic hematopoiesis
0.08
posterior cortical atrophy
0.08
obstructive sleep apnea syndrome
0.08

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

Protein function (UniProt)

Complement C4-B

Precursor of non-enzymatic components of the classical, lectin and GZMK complement pathways, which consist in a cascade of proteins that leads to phagocytosis and breakdown of pathogens and signaling that strengthens the adaptive immune system