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The information on this page was automatically extracted from online scientific databases.

What is the official name of the C5 gene?

The official name of this gene is “complement component 5.”

C5 is the gene's official symbol. The C5 gene is also known by other names, listed below.

Read more about gene names and symbols on the About page.

What is the normal function of the C5 gene?

From NCBI GeneThis link leads to a site outside Genetics Home Reference.:

This gene encodes a component of the complement system, a part of the innate immune system that plays an important role in inflammation, host homeostasis, and host defense against pathogens. The encoded preproprotein is proteolytically processed to generate multiple protein products, including the C5 alpha chain, C5 beta chain, C5a anaphylatoxin and C5b. The C5 protein is comprised of the C5 alpha and beta chains, which are linked by a disulfide bridge. Cleavage of the alpha chain by a convertase enzyme results in the formation of the C5a anaphylatoxin, which possesses potent spasmogenic and chemotactic activity, and the C5b macromolecular cleavage product, a subunit of the membrane attack complex (MAC). Mutations in this gene cause complement component 5 deficiency, a disease characterized by recurrent bacterial infections. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Nov 2015]

From UniProt (CO5_HUMAN)This link leads to a site outside Genetics Home Reference.:

Activation of C5 by a C5 convertase initiates the spontaneous assembly of the late complement components, C5-C9, into the membrane attack complex. C5b has a transient binding site for C6. The C5b-C6 complex is the foundation upon which the lytic complex is assembled.Derived from proteolytic degradation of complement C5, C5 anaphylatoxin is a mediator of local inflammatory process. Binding to the receptor C5AR1 induces a variety of responses including intracellular calcium release, contraction of smooth muscle, increased vascular permeability, and histamine release from mast cells and basophilic leukocytes (PubMed:8182049). C5a is also a potent chemokine which stimulates the locomotion of polymorphonuclear leukocytes and directs their migration toward sites of inflammation.

How are changes in the C5 gene related to health conditions?

Genetics Home Reference provides information about rheumatoid arthritis, which is associated with changes in the C5 gene.
UniProt (CO5_HUMAN)This link leads to a site outside Genetics Home Reference. provides the following information about the C5 gene's known or predicted involvement in human disease.

Complement component 5 deficiency (C5D): A rare defect of the complement classical pathway associated with susceptibility to severe recurrent infections, predominantly by Neisseria gonorrhoeae or Neisseria meningitidis. The disease is caused by mutations affecting the gene represented in this entry.

An association study of C5 haplotypes and genotypes in individuals with chronic hepatitis C virus infection shows that individuals homozygous for the C5_1 haplotype have a significantly higher stage of liver fibrosis than individuals carrying at least 1 other allele.

NCBI GeneThis link leads to a site outside Genetics Home Reference. lists the following diseases or traits (phenotypes) known or believed to be associated with changes in the C5 gene.
  • Eculizumab, poor response to
  • Leiner disease
OMIM.orgThis link leads to a site outside Genetics Home Reference., a catalog designed for genetics professionals and researchers, provides the following information about the C5 gene and its association with health conditions.

Where is the C5 gene located?

Cytogenetic Location: 9q33-q34

Molecular Location on chromosome 9: base pairs 120,952,335 to 121,074,925

The C5 gene is located on the long (q) arm of chromosome 9 between positions 33 and 34.

The C5 gene is located on the long (q) arm of chromosome 9 between positions 33 and 34.

More precisely, the C5 gene is located from base pair 120,952,335 to base pair 121,074,925 on chromosome 9.

See How do geneticists indicate the location of a gene? in the Handbook.

Where can I find additional information about C5?

You and your healthcare professional may find the following resources about C5 helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the C5 gene or gene products?

  • C5a
  • C5b
  • C5D
  • CPAMD4

Where can I find general information about genes?

The Handbook provides basic information about genetics in clear language.

These links provide additional genetics resources that may be useful.

What glossary definitions help with understanding C5?


The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? in the Handbook.

Published: November 23, 2015