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Reviewed December 2015
What is the official name of the C8A gene?
The official name of this gene is “complement component 8, alpha polypeptide.”
C8A is the gene's official symbol. The C8A 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 C8A gene?
The C8A gene provides instructions for making one piece, the alpha subunit, of a protein complex called complement component 8. The alpha subunit is linked to another piece of the complex called the gamma subunit (produced from the C8G gene). These two proteins interact with the beta subunit (produced from the C8B gene) to form complement component 8.
Complement component 8 aids in 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, trigger inflammation, and remove debris from cells and tissues. Complement component 8 combines with several other complement proteins to form the membrane attack complex (MAC), which inserts itself in the outer membrane of bacterial cells. This complex creates a hole (pore) in the membrane, which kills the bacterium. This part of the immune response appears to be especially important for fighting infection by bacteria in the Neisseria genus.
Does the C8A gene share characteristics with other genes?
The C8A 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 C8A gene related to health conditions?
- complement component 8 deficiency - caused by mutations in the C8A gene
- At least two mutations in the C8A gene have been found to cause complement component 8 deficiency type I. This condition is an immune system disorder, known as an immunodeficiency, in which the immune system is not able to protect the body effectively from foreign invaders such as bacteria. People with complement component 8 deficiency have a significantly increased risk of developing recurrent infections, particularly by Neisseria meningitidis, which causes meningitis, a serious condition that involves inflammation of the membranes surrounding the brain and spinal cord.Mutations in the C8A gene alter the blueprint for protein production; if produced, the abnormally short alpha subunit is likely broken down quickly. The resulting shortage of this protein impairs formation of complement component 8. Deficiency of this component prevents formation of membrane attack complexes. Without this part of the immune response, affected individuals are prone to infection, particularly by Neisseria bacteria.
Where is the C8A gene located?
Cytogenetic Location: 1p32
Molecular Location on chromosome 1: base pairs 56,854,770 to 56,918,221
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The C8A gene is located on the short (p) arm of chromosome 1 at position 32.
More precisely, the C8A gene is located from base pair 56,854,770 to base pair 56,918,221 on chromosome 1.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about C8A?
You and your healthcare professional may find the following resources about C8A 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 C8A gene or gene products?
- complement component 8 subunit alpha
- complement component C8 alpha chain preproprotein
See How are genetic conditions and genes named? in the Handbook.
Where can I find general information about genes?
The Handbook provides basic information about genetics in clear language.
- What is DNA?
- What is a gene?
- How do genes direct the production of proteins?
- How can gene mutations affect health and development?
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding C8A?
bacteria ; complement proteins ; deficiency ; gene ; immune response ; immune system ;immunodeficiency ; infection ; inflammation ; protein ; subunit
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (7 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