CFB
Chr 6ADDigenic dominantARcomplement factor B
Also known as: AHUS4, ARMD14, BF, BFD, CFAB, CFBD, FB, FBI12
This gene encodes complement factor B, a component of the alternative pathway of complement activation. Factor B circulates in the blood as a single chain polypeptide. Upon activation of the alternative pathway, it is cleaved by complement factor D yielding the noncatalytic chain Ba and the catalytic subunit Bb. The active subunit Bb is a serine protease which associates with C3b to form the alternative pathway C3 convertase. Bb is involved in the proliferation of preactivated B lymphocytes, while Ba inhibits their proliferation. This gene localizes to the major histocompatibility complex (MHC) class III region on chromosome 6. This cluster includes several genes involved in regulation of the immune reaction. Polymorphisms in this gene are associated with a reduced risk of age-related macular degeneration. The polyadenylation site of this gene is 421 bp from the 5' end of the gene for complement component 2. [provided by RefSeq, Jul 2008]
Primary Disease Associations & Inheritance
Moderate evidence — consider for supplementary testing
2 total gene-disease associations curated
Population Genetics & Constraint
gnomAD v4 — loss-of-function & missense intolerance
More LoF-intolerant than ~75% of genes
Mild missense constraint
ClinVar Variant Classifications
441 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 | 6 | 6 | 0 | 12 |
Likely Pathogenic | 2 | 4 | 1 | 0 | 7 |
VUS | 11 | 178 | 28 | 5 | 222 |
Likely Benign | 0 | 10 | 77 | 90 | 177 |
Benign | 0 | 0 | 4 | 2 | 6 |
Conflicting | — | 17 | |||
| Total | 13 | 198 | 116 | 97 | 441 |
LoF = frameshift, stop gained/lost, canonical splice · Counts from ClinVar esearch · Updated hourly
View in ClinVar →Protein Context — Lollipop Plot
CFB · protein map & ClinVar variants
Showing all ClinVar variants across the protein. Search a specific variant to highlight its position.
OMIM — Genotype-Phenotype Relationships
1 OMIM entry
{Hemolytic uremic syndrome, atypical, susceptibility to, 4}
MIM #612924Molecular basis of disorder known
{Macular degeneration, age-related, 14, reduced risk of}
MIM #615489Molecular basis of disorder known
External Resources
Links to major genomics databases and tools
Variant Interpretation
Population Databases
Gene Resources
Expert Curation
Clinical Trials
Active and recruiting trials from ClinicalTrials.gov
A Trial to See if the Combination of Fianlimab With Cemiplimab Works Better Than Pembrolizumab for Preventing or Delaying Melanoma From Coming Back After it Has Been Removed With Surgery
ACTIVE NOT RECRUITINGThe Role of Cytokines and Regulatory T Lymphocytes in Migraine Pathophysiology.
RECRUITINGDevelopment of a Database to Investigate Digital and Blood-Based Biomarkers and Their Relationship to Tau and Amyloid PET Imaging in Older Participants Who Are Cognitively Normal (CN), Have Mild Cognitive Impairment (MCI), or Have Mild-to-Moderate AD Dementia
RECRUITINGAdipose Tissue Gene Expression and Metabolomics Links to the Gut Microbiome-brain Axis
RECRUITINGInvolvement of the Gut Microbiota-brain Cross-talk in the Loss of Eating Control
RECRUITINGExternal Resources
Links to major genomics databases and tools