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Gene

C4B

complement C4B (Chido/Rodgers blood group)

Summary

Cytogenetic location
6p21.33
Coordinates
Chromosome 6: 32,014,795–32,035,418 (GRCh38)
Exons
41 exons across 20.6 kb
Protein
1,744 amino acids
Inheritance
Autosomal recessive
Also known as
CPAMD3, C4F, CO4, C4B1, C4B3, CH
MANE Select transcript
ENST00000435363.7NM_001002029.4
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

  • Inherited Complement and Properdin Deficiencies

    • Early classical pathway complement deficiency (C1q, C1r/C1s, C2, C4)Autosomal recessive

      Deficiencies of the early components of the classical complement pathway, which are associated with lupus-like autoimmune disease and some bacterial infections.

      • 1 GenCC submitter rates it definitive or strong
      What knowing changes

      Knowing the diagnosis supports early recognition of autoimmune disease and appropriate vaccination.

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.

      • 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.

      • 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 recessive
It takes a changed copy from each parent. With one, you are a carrier and usually unaffected; when both parents are carriers, each child has a one-in-four chance of inheriting two.

How C4B is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Stretches short reads find hard
Chromosome 6, with a bracket where C4B sits. C4B and 70 genes near it on chromosome 6, from 31,525,107 to 32,525,106.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 MbMCCD1: 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 strandABHD16ALY6G6F: 31,706,863–31,710,801, forward strandLY6G6F-LY6G6D: 31,706,904–31,717,918, forward strandLY6G6D: 31,715,285–31,717,919, forward strandMPIG6B: 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 strandC2ZBTB12: 31,899,065–31,902,103, reverse strandZBTB12: 31,927,698–31,952,048, forward strandCFB: 31,945,650–31,952,086, forward strandCFBNELFE: 31,952,087–31,959,079, reverse strandSKIC2: 31,959,025–31,969,852, forward strandSKIC2DXO: 31,969,810–31,972,517, reverse strandDXOWHR1: 31,971,091–31,982,821, forward strandWHR1C4A: 31,981,991–32,005,247, forward strandC4AC4B: 32,014,795–32,035,418, 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-DRAHLA-DRB5: 32,516,622–32,530,369, reverse strandHLA-DRB5Diagram of C4B: 41 exons on the forward strand of chromosome 6Exon 1: 32,014,795–32,014,910, 116 basesExon 2: 32,015,043–32,015,241, 199 basesExon 3: 32,015,456–32,015,657, 202 basesExon 4: 32,015,867–32,015,937, 71 basesExon 5: 32,016,016–32,016,104, 89 basesExon 6: 32,016,323–32,016,405, 83 basesExon 7: 32,016,576–32,016,672, 97 basesExon 8: 32,016,811–32,016,916, 106 basesExon 9: 32,017,014–32,017,146, 133 basesExon 10: 32,023,930–32,024,045, 116 basesExon 11: 32,024,145–32,024,324, 180 basesExon 12: 32,024,470–32,024,652, 183 basesExon 13: 32,024,785–32,024,970, 186 basesExon 14: 32,025,124–32,025,282, 159 basesExon 15: 32,025,534–32,025,660, 127 basesExon 16: 32,025,828–32,025,902, 75 basesExon 17: 32,026,163–32,026,360, 198 basesExon 18: 32,026,452–32,026,563, 112 basesExon 19: 32,026,654–32,026,724, 71 basesExon 20: 32,026,983–32,027,122, 140 basesExon 21: 32,027,236–32,027,445, 210 basesExon 22: 32,027,690–32,027,741, 52 basesExon 23: 32,027,843–32,027,932, 90 basesExon 24: 32,028,068–32,028,277, 210 basesExon 25: 32,028,457–32,028,532, 76 basesExon 26: 32,028,693–32,028,849, 157 basesExon 27: 32,028,945–32,029,061, 117 basesExon 28: 32,029,167–32,029,338, 172 basesExon 29: 32,029,566–32,029,798, 233 basesExon 30: 32,029,881–32,030,048, 168 basesExon 31: 32,030,442–32,030,501, 60 basesExon 32: 32,031,551–32,031,644, 94 basesExon 33: 32,031,742–32,031,928, 187 basesExon 34: 32,032,043–32,032,133, 91 basesExon 35: 32,032,224–32,032,298, 75 basesExon 36: 32,033,790–32,033,892, 103 basesExon 37: 32,034,058–32,034,147, 90 basesExon 38: 32,034,233–32,034,331, 99 basesExon 39: 32,034,514–32,034,597, 84 basesExon 40: 32,034,860–32,034,992, 133 basesExon 41: 32,035,136–32,035,418, 283 bases125415′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 5.4 kb of the gene's 20.6 kb; 5,235 of those bases code for the protein.

How a genome test reads C4B

2

positions in C4B where ClinVar classes a change as pathogenic or likely pathogenic

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

  • Low mappability (1 site)Regions where 100 bp or 250 bp reads cannot be placed uniquely.
  • MHC (2 sites)The major histocompatibility complex (HLA genes), highly polymorphic and poorly represented by a single reference.
  • Segmental duplications (2 sites)Copies of at least 1 kb sharing at least 90% identity with another part of the genome (paralogues, pseudogenes); reads may align to the wrong copy.

A whole genome covers all 20.6 kb of C4B, introns included, not only the 5.4 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.). C4B gene: complement C4B (Chido/Rodgers blood group). Retrieved 16 October 2026, from https://dantelabs.com/genes/c4b

Vancouver

Dante Labs. C4B gene: complement C4B (Chido/Rodgers blood group) [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/c4b

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