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Gene

CFB

complement factor B

Summary

Cytogenetic location
6p21.33
Coordinates
Chromosome 6: 31,946,095–31,952,084 (GRCh38)
Exons
18 exons across 6 kb
Protein
764 amino acids
Inheritance
Autosomal dominant
Also known as
H2-Bf
Previous symbols
BFD, BF
MANE Select transcript
ENST00000425368.7NM_001710.6
Locus type
gene with protein product
  • Very high
  • Confident
  • Low
  • Very low

Reference genomeGRCh38

Positions on gene and variant pages follow this choice, in this browser.

Curated reports relevant to this gene

  • Hemolytic Uremic Syndrome, Interstitial Nephritis

    • Atypical Hemolytic-Uremic Syndrome With B Factor AnomalyAutosomal dominant
      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
    • Atypical Hemolytic Uremic Syndrome With Complement Gene AbnormalityAutosomal dominant
      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
    • Atypical Hemolytic-Uremic SyndromeAutosomal dominant

      A rare, genetic thrombotic microangiopathy due to dysregulation of the alternative complement pathway and characterized by the triad of hemolytic anemia, thrombocytopenia, and acute renal dysfunction.

      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
    • Hemolytic-Uremic Syndrome

      Acute kidney injury associated with microangiopathic hemolytic anemia and thrombocytopenia.

      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
    • Hereditary Hemolytic Uremic Syndrome
      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong

Broader groupings

  • Other Inborn Errors of Immunity

    • Inborn error of immunity

      One of 114 genes linked to it

      Inherited disorders of the immune system caused by changes in single genes, affecting how the body fights infection or regulates inflammation.

      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
    • Immunodeficiency Disease

      One of 170 genes linked to it

      Disease in which there is a deficiency or defect in the mechanisms of immunity, either cellular or humoral.

      • ClinGen rates the link moderate
      • 1 GenCC submitter rates it definitive or strong
      What knowing changes

      HSCT for SCID and severe PIDs; immunoglobulin replacement (IVIG/SCIG) for antibody deficiencies; leniolisib (Joenja, FDA 2023) for APDS; gene therapy for ADA-SCID; abatacept for CTLA4/LRBA deficiency; prophylactic antibiotics; G-CSF for CGD

Inheritance

Autosomal dominant
One changed copy, from either parent, is enough. A parent who has one passes it on to each child with a one-in-two chance.

How CFB is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
  • Stretches short reads find hard
Chromosome 6, with a bracket where CFB sits. CFB and 70 genes near it on chromosome 6, from 31,449,090 to 32,449,089.Chromosome 66p21.33p25.3p25.2p25.1p24.3p24.2p24.1p23p22.3p22.2p22.1p21.33p21.32p21.31p21.2p21.1p12.3p12.2p12.1p11.2p11.1q11.1q11.2q12q13q14.1q14.2q14.3q15q16.1q16.2q16.3q21q22.1q22.2q22.31q22.32q22.33q23.1q23.2q23.3q24.1q24.2q24.3q25.1q25.2q25.3q26q2731.6 Mb31.8 Mb32 Mb32.2 Mb32.4 MbMICB: 31,494,881–31,511,124, forward strandMICBMCCD1: 31,528,962–31,530,232, forward strandDDX39B: 31,530,217–31,542,451, reverse strandDDX39BATP6V1G2-DDX39B: 31,530,219–31,546,608, reverse strandATP6V1G2: 31,544,444–31,548,427, reverse strandNFKBIL1: 31,546,870–31,558,829, forward strandLTA: 31,572,054–31,574,324, forward strandLTATNF: 31,575,558–31,578,336, forward strandLTB: 31,580,525–31,582,522, reverse strandLST1: 31,581,065–31,588,911, forward strandLST1NCR3: 31,588,895–31,593,217, reverse strandNCR3AIF1: 31,615,214–31,617,025, forward strandAIF1PRRC2A: 31,620,675–31,637,771, forward strandPRRC2A: 31,622,774–31,622,860, forward strand: 31,623,874–31,625,499, forward strandBAG6: 31,638,543–31,652,747, reverse strandAPOM: 31,652,416–31,658,214, forward strandC6orf47: 31,658,298–31,660,778, reverse strandGPANK1: 31,661,228–31,666,283, reverse strandCSNK2B: 31,665,227–31,670,343, forward strand: 31,666,102–31,673,546, forward strandLY6G5B: 31,669,976–31,673,776, forward strandLY6G5C: 31,676,684–31,684,040, reverse strandLY6G5CABHD16A: 31,686,954–31,703,391, reverse strandLY6G6F: 31,706,863–31,710,801, forward strandLY6G6F-LY6G6D: 31,706,904–31,717,918, forward strandLY6G6D: 31,715,285–31,717,919, forward strandLY6G6DMPIG6B: 31,718,594–31,726,714, forward strandLY6G6C: 31,718,648–31,721,746, reverse strandDDAH2: 31,726,586–31,730,617, reverse strandCLIC1: 31,730,579–31,740,558, reverse strandMSH5: 31,739,677–31,762,678, forward strandMSH5MSH5-SAPCD1: 31,740,020–31,764,851, forward strandSAPCD1: 31,762,656–31,764,851, forward strandVWA7: 31,765,590–31,777,328, reverse strandVWA7VARS1: 31,777,518–31,795,975, reverse strandLSM2: 31,797,019–31,806,992, reverse strandLSM2HSPA1L: 31,809,619–31,815,788, reverse strandHSPA1A: 31,815,543–31,817,994, forward strandHSPA1AHSPA1B: 31,827,738–31,830,254, forward strandHSPA1BNEU1: 31,857,063–31,862,905, reverse strandNEU1SLC44A4: 31,863,173–31,879,198, reverse strandSLC44A4EHMT2: 31,879,758–31,897,723, reverse strandEHMT2C2: 31,897,785–31,945,677, forward strandZBTB12: 31,899,065–31,902,103, reverse strandZBTB12: 31,927,698–31,952,048, forward strandCFB: 31,946,095–31,952,084, forward strandCFBNELFE: 31,952,087–31,959,079, reverse strandNELFESKIC2: 31,959,025–31,969,852, forward strandSKIC2DXO: 31,969,810–31,972,517, reverse strandWHR1: 31,971,091–31,982,821, forward strandC4A: 31,981,991–32,005,247, forward strandC4B: 32,014,725–32,035,975, forward strandC4BCYP21A2: 32,038,297–32,042,321, forward strandCYP21A2TNXB: 32,041,153–32,115,334, reverse strandTNXBATF6B: 32,115,264–32,128,255, reverse strandATF6BFKBPL: 32,128,697–32,131,070, reverse strandFKBPLPPT2: 32,146,580–32,163,679, forward strandPRRT1: 32,147,292–32,153,083, reverse strandPRRT1: 32,150,495–32,154,373, reverse strandPPT2-EGFL8: 32,153,845–32,171,978, forward strandEGFL8: 32,163,918–32,171,980, forward strandAGPAT1: 32,167,118–32,178,112, reverse strandRNF5: 32,178,391–32,184,769, forward strandAGER: 32,180,963–32,184,365, reverse strandPBX2: 32,184,733–32,190,278, reverse strandGPSM3: 32,190,766–32,195,523, reverse strandNOTCH4: 32,194,843–32,224,111, reverse strandNOTCH4TSBP1: 32,288,526–32,371,907, reverse strandTSBP1BTNL2: 32,391,481–32,407,181, reverse strandBTNL2HLA-DRA: 32,439,870–32,445,181, forward strandHLA-DRADiagram of CFB: 18 exons on the forward strand of chromosome 6Exon 6: 3 known disease-causing sitesExon 7: 2 known disease-causing sitesExon 8: 4 known disease-causing sitesExon 10: 2 known disease-causing sitesExon 1: 31,946,095–31,946,285, 191 basesExon 2: 31,946,373–31,946,606, 234 basesExon 3: 31,947,007–31,947,192, 186 basesExon 4: 31,947,348–31,947,521, 174 basesExon 5: 31,947,742–31,947,843, 102 basesExon 6: 31,947,945–31,948,081, 137 basesExon 7: 31,948,374–31,948,512, 139 basesExon 8: 31,948,830–31,948,961, 132 basesExon 9: 31,949,243–31,949,344, 102 basesExon 10: 31,949,420–31,949,557, 138 basesExon 11: 31,950,050–31,950,147, 98 basesExon 12: 31,950,286–31,950,403, 118 basesExon 13: 31,950,619–31,950,772, 154 basesExon 14: 31,950,868–31,950,944, 77 basesExon 15: 31,951,144–31,951,244, 101 basesExon 16: 31,951,341–31,951,473, 133 basesExon 17: 31,951,555–31,951,604, 50 basesExon 18: 31,951,875–31,952,084, 210 bases1234567891011121314151617185′3′

Exons of the gene's MANE Select transcript (release v1.5), from NCBI and EMBL-EBI, on the GRCh38 reference genome.

Chromosome bands from UCSC's GRCh38 ideogram (2022-10-29).

Nearby genes from Ensembl release 116, on GRCh38.

Exons make up 2.5 kb of the gene's 6 kb; 2,295 of those bases code for the protein.

How a genome test reads CFB

12

positions in CFB where ClinVar classes a change as pathogenic or likely pathogenic

12 of them (100%) fall in regions short reads find hard.

  • MHC (12 sites)The major histocompatibility complex (HLA genes), highly polymorphic and poorly represented by a single reference.

A whole genome covers all 6 kb of CFB, introns included, not only the 2.5 kb of exons.

Where this comes from

  • HGNC: the gene's symbol, name, other symbols and location.
  • MANE Select v1.5, from NCBI and EMBL-EBI: the transcript, its exons and coding sequence.
  • GenCC and ClinGen, released 2026-10-16: which conditions the gene is linked to, and how strongly.
  • The ACMG secondary findings list, SF v3.2.
  • ClinVar and the GIAB stratifications: known disease-causing sites, and the regions short reads find hard.
  • The Human Phenotype Ontology, release 2026-09-01: the traits linked to the gene. Find out more at hpo.jax.org.
  • Data release 2026.10.16-c6eea6bf.

Cite this page

APA

Dante Labs. (n.d.). CFB gene: complement factor B. Retrieved 17 October 2026, from https://dantelabs.com/genes/cfb

Vancouver

Dante Labs. CFB gene: complement factor B [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/cfb

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