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Reviewed June 2014

What is the official name of the C2 gene?

The official name of this gene is “complement component 2.”

C2 is the gene's official symbol. The C2 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 C2 gene?

The C2 gene provides instructions for making the complement component 2 protein. This protein helps regulate a part of the body's immune response known as the complement system. The complement system is a group of proteins that work together to destroy foreign invaders (such as bacteria and viruses), trigger inflammation, and remove debris from cells and tissues. When a foreign invader is detected, the complement pathway is turned on (activated) and the complement component 2 protein attaches (binds) to a similar protein called complement component 4. Together, these proteins form a complex called C3 convertase, which triggers further activation of the pathway, allowing the proteins of the complement system to participate in an immune response.

Does the C2 gene share characteristics with other genes?

The C2 gene belongs to a family of genes called complement (complement system).

A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? in the Handbook.

How are changes in the C2 gene related to health conditions?

complement component 2 deficiency - caused by mutations in the C2 gene

At least five mutations in the C2 gene have been found to cause complement component 2 deficiency. This disorder reduces the normal function of the immune system, resulting in an increased risk for infections and autoimmune disorders such as systemic lupus erythematosus (SLE). Autoimmune disorders occur when the immune system malfunctions and attacks the body's tissues and organs.

More than 90 percent of people with complement component 2 deficiency have a mutation that deletes 28 DNA building blocks (nucleotides) from the C2 gene. This mutation prevents the production of any complement component 2 protein. Without this protein to form C3 convertase, activation of the complement system is stalled. As a result, the complement system's ability to fight infections is diminished. It is unclear how complement component 2 deficiency leads to increased susceptibility to autoimmune disorders. Researchers speculate that the dysfunctional complement system is unable to distinguish what it should attack, and it sometimes attacks normal tissues, leading to autoimmunity. Alternatively, the dysfunctional complement system may perform partial attacks on invading molecules, which leaves behind foreign fragments that are difficult to distinguish from the body's tissues, so the complement system sometimes attacks the body's own cells. It is likely that other factors, both genetic and environmental, play a role in the variability of the signs and symptoms of complement component 2 deficiency.

Genetics Home Reference provides information about age-related macular degeneration, which is also associated with changes in the C2 gene.

Where is the C2 gene located?

Cytogenetic Location: 6p21.3

Molecular Location on chromosome 6: base pairs 31,897,785 to 31,945,674

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBIThis link leads to a site outside Genetics Home Reference.)

The C2 gene is located on the short (p) arm of chromosome 6 at position 21.3.

The C2 gene is located on the short (p) arm of chromosome 6 at position 21.3.

More precisely, the C2 gene is located from base pair 31,897,785 to base pair 31,945,674 on chromosome 6.

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

Where can I find additional information about C2?

You and your healthcare professional may find the following resources about C2 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 C2 gene or gene products?

  • ARMD14
  • C3/C5 convertase
  • CO2
  • complement C2
  • complement component C2

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 C2?

autoimmune ; autoimmunity ; bacteria ; deficiency ; DNA ; gene ; immune response ; immune system ; inflammation ; mutation ; protein ; susceptibility

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.

See also Understanding Medical Terminology.

References (5 links)


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.

Reviewed: June 2014
Published: February 8, 2016