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Gene

C1QA

complement C1q A chain

Summary

Cytogenetic location
1p36.12
Coordinates
Chromosome 1: 22,636,628–22,639,678 (GRCh38)
Exons
3 exons across 3.1 kb
Protein
245 amino acids
Inheritance
Autosomal recessive
MANE Select transcript
ENST00000374642.8NM_015991.4
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

  • Autoimmune Disease

    • A disorder resulting from loss of function or tissue destruction of an organ or multiple organs, arising from humoral or cellular immune responses of the individual to their own tissue constituents. It may be systemic (e.g., systemic lupus erythematosus), or organ specific, (e.g., thyroiditis).

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

  • 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.

  • Systemic Lupus Erythematosus

    • An autoimmune multi-organ disease typically associated with vasculopathy and autoantibody production. Most patients have antinuclear antibodies (ANA). The presence of anti-dsDNA or anti-Smith antibodies are highly-specific.

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

      Standard SLE: hydroxychloroquine, mycophenolate, belimumab, anifrolumab; Complement-deficient lupus: FFP replacement; Interferonopathy: anifrolumab, JAK inhibitors; All: sun protection, cardiovascular risk management, pregnancy planning

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 C1QA is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
Chromosome 1, with a bracket where C1QA sits. C1QA and 12 genes near it on chromosome 1, from 22,138,153 to 23,138,152.Chromosome 11p36.12p36.33p36.32p36.31p36.23p36.22p36.21p36.13p36.12p36.11p35.3p35.2p35.1p34.3p34.2p34.1p33p32.3p32.2p32.1p31.3p31.2p31.1p22.3p22.2p22.1p21.3p21.2p21.1p13.3p13.2p13.1p12p11.2p11.1q11q12q21.1q21.2q21.3q22q23.1q23.2q23.3q24.1q24.2q24.3q25.1q25.2q25.3q31.1q31.2q31.3q32.1q32.2q32.3q41q42.11q42.12q42.13q42.2q42.3q43q4422.2 Mb22.4 Mb22.6 Mb22.8 Mb23 MbWNT4: 22,117,313–22,143,969, reverse strandWNT4ZBTB40: 22,428,838–22,531,157, forward strandZBTB40EPHA8: 22,563,461–22,603,595, forward strandEPHA8: 22,636,506–22,644,067, forward strandC1QA: 22,636,628–22,639,678, forward strandC1QAC1QC: 22,642,558–22,648,122, forward strandC1QCC1QB: 22,652,713–22,661,637, forward strandC1QBEPHB2: 22,710,798–22,921,500, forward strandEPHB2LACTBL1: 22,953,043–22,972,866, reverse strandLACTBL1TEX46: 23,010,833–23,019,100, reverse strandTEX46KDM1A: 23,019,395–23,083,704, forward strandKDM1ALUZP1: 23,084,030–23,178,152, reverse strandLUZP1: 23,094,326–23,094,376, reverse strandDiagram of C1QA: 3 exons on the forward strand of chromosome 1Exon 2: 1 known disease-causing siteExon 3: 3 known disease-causing sitesExon 1: 22,636,628–22,636,702, 75 basesExon 2: 22,637,610–22,637,779, 170 basesExon 3: 22,638,833–22,639,678, 846 bases1235′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 1.1 kb of the gene's 3.1 kb; 738 of those bases code for the protein.

How a genome test reads C1QA

4

positions in C1QA where ClinVar classes a change as pathogenic or likely pathogenic

None of them falls in a region short reads find hard.

A whole genome covers all 3.1 kb of C1QA, introns included, not only the 1.1 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.). C1QA gene: complement C1q A chain. Retrieved 16 October 2026, from https://dantelabs.com/genes/c1qa

Vancouver

Dante Labs. C1QA gene: complement C1q A chain [Internet]. [cited 16 October 2026]. Available from: https://dantelabs.com/genes/c1qa

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