CYP2C9 - cytochrome P450, family 2, subfamily C, polypeptide 9 - Genetics Home Reference

CYP2C9 - cytochrome P450, family 2, subfamily C, polypeptide 9 - Genetics Home Reference

CYP2C9

On this page:

 

• Name 
• Normal function 
• Gene families 
• Genetic changes 
• Gene location
• Additional information 
• Other names 
• About genes 
• Glossary definitions

What is the official name of the CYP2C9 gene?

The official name of this gene is “cytochrome P450, family 2, subfamily C, polypeptide 9.”

CYP2C9 is the gene's official symbol. The CYP2C9 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 CYP2C9 gene?

The CYP2C9 gene provides instructions for making an enzyme that is found in a cell structure called the endoplasmic reticulum, which is involved in protein processing and transport. The CYP2C9 enzyme breaks down (metabolizes) compounds including steroid hormones and fatty acids. The CYP2C9 enzyme also plays a major role in breaking down the drug warfarin, which thins the blood and prevents blood clots from forming. This enzyme also assists in metabolizing other drugs such as ibuprofen, which reduces inflammation.

Does the CYP2C9 gene share characteristics with other genes?

The CYP2C9 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 CYP2C9 gene related to health conditions?

warfarin sensitivity - associated with the CYP2C9 gene

Certain common CYP2C9 gene variations (polymorphisms) that decrease the activity of the CYP2C9 enzyme can result in a condition called warfarin sensitivity. The altered enzyme slows the breakdown (metabolism) of warfarin, allowing the drug to remain active in the body for a longer period of time. People with warfarin sensitivity take longer than usual to metabolize warfarin and may require lower doses of the drug than are usually prescribed.

The two most common CYP2C9 gene polymorphisms change single protein building blocks (amino acids) in the CYP2C9 enzyme. The first one, known as CYP2C9*2, replaces the amino acid arginine with the amino acid cysteine at position 144, written as Arg144Cys or R144C. The CYP2C9*2 polymorphism leads to a decrease in warfarin metabolism to such a degree that prescription doses are typically reduced by one-third in people with this variation. The second polymorphism, known as CYP2C9*3, replaces the amino acid isoleucine with the amino acid leucine at position 359, written as Ile359Leu or I359L. In people with the CYP2C9*3polymorphism, prescription doses are typically reduced by one-fifth. In rare cases in which individuals have both CYP2C9*2 and CYP2C9*3 polymorphisms, the enzyme activity is severely decreased and metabolism of warfarin is very slow. If people with warfarin sensitivity take the average dose (or more) of warfarin, they are at risk of an overdose, which can cause abnormal bleeding in the brain, gastrointestinal tract, or other tissues, and may lead to serious health problems or death.

Where is the CYP2C9 gene located?

Cytogenetic Location: 10q24

Molecular Location on chromosome 10: base pairs 94,938,657 to 94,989,390

The CYP2C9 gene is located on the long (q) arm of chromosome 10 at position 24.

More precisely, the CYP2C9 gene is located from base pair 94,938,657 to base pair 94,989,390 on chromosome 10.

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

Where can I find additional information about CYP2C9?

You and your healthcare professional may find the following resources about CYP2C9 helpful.

• Educational resources - Information pages
  Biochemistry (fifth edition, 2002): Blood-Clotting Cascade
• Genetic Testing Registry - Repository of genetic test information (1 link)

You may also be interested in these resources, which are designed for genetics professionals and researchers.

• PubMed - Recent literature
• OMIM - Genetic disorder catalog
• Research Resources - Tools for researchers (5 links)

What other names do people use for the CYP2C9 gene or gene products?

• CYPIIC9
• cytochrome P450 2C9
• cytochrome P450, family 2, subfamily C, polypeptide 9 gene
• cytochrome P-450MP
• cytochrome P450 MP-4
• cytochrome P450 MP-8
• cytochrome P450 PB-1
• P450 MP-4
• S-mephenytoin 4-hydroxylase
• S-mephenytoin 4-hydroxylase, human
• warfarin-7-hydroxylase, human

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.

• Genetics Education
• Human Genome Project
• Resources for Genetics Researchers

What glossary definitions help with understanding CYP2C9?

acids ; amino acid ; arginine ; breakdown ; cell ; cysteine ; cytochrome P450 ;endoplasmic reticulum ; enzyme ; fatty acids ; gastrointestinal ; gene ; inflammation ; isoleucine ;leucine ; metabolism ; pharmacogenetics ; pharmacogenomics ; polymorphism ; protein ; sensitivity ;warfarin

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