|A service of the U.S. National Library of Medicine®|
On this page:
Reviewed March 2014
What is the official name of the POR gene?
The official name of this gene is “P450 (cytochrome) oxidoreductase.”
POR is the gene's official symbol. The POR 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 POR gene?
The POR gene provides instructions for making the enzyme cytochrome P450 oxidoreductase. This enzyme is required for the normal functioning of more than 50 enzymes in the cytochrome P450 family. Cytochrome P450 enzymes are involved in the formation (synthesis) and breakdown (metabolism) of various molecules and chemicals within cells.
Cytochrome P450 enzymes are critical for the synthesis of cholesterol and steroid hormones. Cholesterol is a substance that has many essential functions both before and after birth, including roles in the production of steroid hormones and in the formation and growth of bones. Steroid hormones are needed for normal development and reproduction. This group of hormones includes testosterone and estrogen, which are essential for normal sexual development and reproduction; corticosteroids, which are involved in the body's response to stress; and aldosterone, which helps regulate the body's salt and water balance.
Additionally, cytochrome P450 enzymes are involved in the metabolism of ingested substances, such as medications, in the liver. Because cytochrome P450 oxidoreductase helps regulate the activity of these enzymes, researchers suspect that normal variations in the POR gene may influence a person's response to particular drugs (drug metabolism).
How are changes in the POR gene related to health conditions?
Where is the POR gene located?
Cytogenetic Location: 7q11.2
Molecular Location on chromosome 7: base pairs 75,915,102 to 75,986,855
(Homo sapiens Annotation Release 107, GRCh38.p2) (
The POR gene is located on the long (q) arm of chromosome 7 at position 11.2.
More precisely, the POR gene is located from base pair 75,915,102 to base pair 75,986,855 on chromosome 7.
See How do geneticists indicate the location of a gene? in the Handbook.
Where can I find additional information about POR?
You and your healthcare professional may find the following resources about POR 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 POR 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 POR?
acids ; aldosterone ; bone formation ; breakdown ; cholesterol ; cytochrome P450 ; deficiency ; electron ; enzyme ; gene ; metabolism ; molecule ; oxidoreductase ; pharmacogenomics ; protein ; puberty ; reproduction ; stress ; syndrome ; synthesis ; testosterone
You may find definitions for these and many other terms in the Genetics Home Reference Glossary.
See also Understanding Medical Terminology.
References (9 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.