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Reviewed February 2010
What is the official name of the CYP21A2 gene?
The official name of this gene is “cytochrome P450 family 21 subfamily A member 2.”
CYP21A2 is the gene's official symbol. The CYP21A2 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 CYP21A2 gene?
The CYP21A2 gene provides instructions for making an enzyme called 21-hydroxylase, which is part of the cytochrome P450 family of enzymes. Cytochrome P450 enzymes are involved in many processes in the body, such as assisting with reactions that break down drugs and helping to produce cholesterol, certain hormones, and fats (lipids).
The 21-hydroxylase enzyme is found in the adrenal glands, which are located on top of the kidneys and produce a variety of hormones that regulate many essential functions in the body. 21-hydroxylase plays a role in producing hormones called cortisol and aldosterone. Cortisol helps maintain blood sugar levels, protects the body from stress, and suppresses inflammation. Aldosterone is sometimes called the salt-retaining hormone because it regulates the amount of salt retained by the kidneys. The retention of salt affects fluid levels in the body and blood pressure.
Does the CYP21A2 gene share characteristics with other genes?
The CYP21A2 gene belongs to a family of genes called CYP (cytochrome P450s).
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 CYP21A2 gene related to health conditions?
Where is the CYP21A2 gene located?
Cytogenetic Location: 6p21.3
Molecular Location on chromosome 6: base pairs 32,038,316 to 32,041,670
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The CYP21A2 gene is located on the short (p) arm of chromosome 6 at position 21.3.
More precisely, the CYP21A2 gene is located from base pair 32,038,316 to base pair 32,041,670 on chromosome 6.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about CYP21A2?
You and your healthcare professional may find the following resources about CYP21A2 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 CYP21A2 gene or gene products?
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.
These links provide additional genetics resources that may be useful.
What glossary definitions help with understanding CYP21A2?
acids ; adrenal glands ; aldosterone ; androgens ; cholesterol ; chromosome ; congenital ; cytochrome P450 ; deficiency ; DNA ; enzyme ; gene ; gene conversion ; hormone ; hyperplasia ; inflammation ; protein ; pseudogene ; stress ; wasting
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (10 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.