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Reviewed August 2012

What is the official name of the CYBA gene?

The official name of this gene is “cytochrome b-245, alpha polypeptide.”

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

The CYBA gene provides instructions for making a protein called cytochrome b-245, alpha subunit (also known as p22-phox). This protein is one part (subunit) of a group of proteins that forms an enzyme complex called NADPH oxidase, which plays an essential role in the immune system. Within this complex, the cytochrome b-245, alpha subunit has a beta subunit partner (produced from the CYBB gene). Both alpha and beta subunits are required for either to function and the NADPH oxidase complex requires both subunits in order to be functional. NADPH oxidase is primarily active in immune system cells called phagocytes. These cells catch and destroy foreign invaders such as bacteria and fungi. NADPH oxidase is also thought to regulate the activity of immune cells called neutrophils. These cells play a role in adjusting the inflammatory response to optimize healing and reduce injury to the body.

The presence of foreign invaders stimulates phagocytes and triggers the assembly of NADPH oxidase. This enzyme participates in a chemical reaction that converts oxygen to a toxic molecule called superoxide. Superoxide is used to generate several other compounds, including hydrogen peroxide (a strong disinfectant) and hypochlorous acid (the active ingredient in bleach). These highly reactive, toxic substances are known as reactive oxygen species. Phagocytes use these substances to kill foreign invaders, preventing them from reproducing in the body and causing illness.

Does the CYBA gene share characteristics with other genes?

The CYBA gene belongs to a family of genes called CYB (cytochrome b).

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 CYBA gene related to health conditions?

chronic granulomatous disease - caused by mutations in the CYBA gene

More than 40 mutations in the CYBA gene have been found to cause chronic granulomatous disease. People with this disorder are at increased risk of developing recurrent episodes of infection and inflammation due to a weakened immune system. Mutations in the CYBA gene cause less than 5 percent of all cases of this condition. Most of these mutations change single building blocks of protein (amino acids) in the cytochrome b-245, alpha subunit or cause it to be abnormally short and nonfunctional. An altered protein not only diminishes the function of the alpha subunit, but the function of its beta subunit partner as well. Without these subunits, NADPH oxidase cannot assemble or function properly. As a result, phagocytes are unable to produce reactive oxygen species to kill foreign invaders, and neutrophil activity is not regulated. A lack of NADPH oxidase leaves affected individuals vulnerable to many types of infection and excessive inflammation.

Where is the CYBA gene located?

Cytogenetic Location: 16q24

Molecular Location on chromosome 16: base pairs 88,643,289 to 88,651,085

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

The CYBA gene is located on the long (q) arm of chromosome 16 at position 24.

The CYBA gene is located on the long (q) arm of chromosome 16 at position 24.

More precisely, the CYBA gene is located from base pair 88,643,289 to base pair 88,651,085 on chromosome 16.

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

Where can I find additional information about CYBA?

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

  • cytochrome b-245 light chain
  • cytochrome b(558) alpha chain
  • cytochrome b558 subunit alpha
  • cytochrome b, alpha polypeptide
  • cytochrome b light chain
  • flavocytochrome b-558 alpha polypeptide
  • neutrophil cytochrome b 22 kDa polypeptide
  • p22phox
  • superoxide-generating NADPH oxidase light chain subunit

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 CYBA?

acids ; bacteria ; chronic ; enzyme ; gene ; granulomatous ; hydrogen peroxide ; hypochlorous acid ; immune system ; infection ; inflammation ; injury ; innate immunity ; molecule ; neutrophils ; oxidase ; oxygen ; phagocytes ; protein ; reactive oxygen species ; subunit ; toxic

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

See also Understanding Medical Terminology.

References (6 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: August 2012
Published: February 8, 2016