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Gene

C1S

complement C1s

Summary

Cytogenetic location
12p13.31
Coordinates
Chromosome 12: 7,060,718–7,071,032 (GRCh38)
Exons
12 exons across 10.3 kb
Protein
688 amino acids
Inheritance
Autosomal recessive
MANE Select transcript
ENST00000360817.10NM_001734.5
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.

      • 2 GenCC submitters rate it definitive or strong
      What knowing changes

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

  • Ehlers-Danlos Syndrome

      • 2 GenCC submitters rate 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.

      • 2 GenCC submitters rate 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.

      • 2 GenCC submitters rate 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 C1S is laid out

  • Coding sequence
  • Untranslated region
  • Intron
  • Direction of transcription
  • Known disease-causing sites
Chromosome 12, with a bracket where C1S sits. C1S and 38 genes near it on chromosome 12, from 6,565,875 to 7,565,874.Chromosome 1212p13.31p13.33p13.32p13.31p13.2p13.1p12.3p12.2p12.1p11.23p11.22p11.21p11.1q11q12q13.11q13.12q13.13q13.2q13.3q14.1q14.2q14.3q15q21.1q21.2q21.31q21.32q21.33q22q23.1q23.2q23.3q24.11q24.12q24.13q24.21q24.22q24.23q24.31q24.32q24.336.6 Mb6.8 Mb7 Mb7.2 Mb7.4 MbNOP2: 6,556,863–6,568,691, reverse strandNOP2: 6,556,886–6,607,367, reverse strandCHD4: 6,570,081–6,614,982, reverse strandCHD4LPAR5: 6,618,835–6,636,444, reverse strandLPAR5ACRBP: 6,638,075–6,647,441, reverse strandACRBPING4: 6,650,282–6,663,180, reverse strandING4ZNF384: 6,665,037–6,689,572, reverse strandZNF384PIANP: 6,693,791–6,700,859, reverse strandPIANPCOPS7A: 6,724,014–6,732,462, forward strandCOPS7AMLF2: 6,747,986–6,768,932, reverse strandMLF2PTMS: 6,765,516–6,770,952, forward strandPTMSLAG3: 6,772,360–6,778,455, forward strandLAG3CD4: 6,786,858–6,820,807, forward strandCD4GPR162: 6,821,624–6,829,972, forward strandP3H3: 6,828,220–6,839,867, forward strandGNB3: 6,839,954–6,847,393, forward strandCDCA3: 6,844,723–6,852,353, reverse strandUSP5: 6,852,098–6,866,632, forward strandUSP5TPI1: 6,867,119–6,878,513, forward strandTPI1SPSB2: 6,870,934–6,889,358, reverse strandSPSB2LRRC23: 6,873,455–6,914,243, forward strandLRRC23ENO2: 6,913,745–6,923,970, forward strandENO2ATN1: 6,924,454–6,942,322, forward strandC12orf57: 6,942,919–6,946,009, forward strandRNU7-1: 6,943,816–6,943,878, forward strandPTPN6: 6,946,417–6,961,316, forward strandPHB2: 6,965,327–6,970,841, reverse strandPHB2EMG1: 6,970,765–6,979,939, forward strandEMG1: 6,970,921–6,997,428, forward strandLPCAT3: 6,972,027–7,018,779, reverse strandLPCAT3C1S: 7,060,718–7,071,032, forward strandC1SC1R: 7,080,213–7,092,873, reverse strandC1RC1RL: 7,089,587–7,109,245, reverse strandC1RLRBP5: 7,115,736–7,128,891, reverse strandRBP5CLSTN3: 7,128,077–7,158,945, forward strandCLSTN3PEX5: 7,188,653–7,218,574, forward strandPEX5ACSM4: 7,304,072–7,328,719, forward strandACSM4CD163L1: 7,346,685–7,479,897, reverse strandCD163L1CD163: 7,469,417–7,503,911, reverse strandCD163Diagram of C1S: 12 exons on the forward strand of chromosome 12Exon 4: 1 known disease-causing siteExon 8: 2 known disease-causing sitesExon 12: 4 known disease-causing sitesExon 1: 7,060,718–7,060,877, 160 basesExon 2: 7,061,839–7,061,917, 79 basesExon 3: 7,062,475–7,062,682, 208 basesExon 4: 7,062,890–7,063,067, 178 basesExon 5: 7,064,267–7,064,392, 126 basesExon 6: 7,065,100–7,065,299, 200 basesExon 7: 7,065,817–7,065,970, 154 basesExon 8: 7,066,518–7,066,633, 116 basesExon 9: 7,067,039–7,067,117, 79 basesExon 10: 7,067,643–7,067,771, 129 basesExon 11: 7,068,456–7,068,530, 75 basesExon 12: 7,069,855–7,071,032, 1,178 bases1234567891011125′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 2.7 kb of the gene's 10.3 kb; 2,067 of those bases code for the protein.

How a genome test reads C1S

7

positions in C1S 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 10.3 kb of C1S, introns included, not only the 2.7 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.). C1S gene: complement C1s. Retrieved 17 October 2026, from https://dantelabs.com/genes/c1s

Vancouver

Dante Labs. C1S gene: complement C1s [Internet]. [cited 17 October 2026]. Available from: https://dantelabs.com/genes/c1s

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