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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed October 2015

What is the official name of the BRCA1 gene?

The official name of this gene is “breast cancer 1.”

BRCA1 is the gene's official symbol. The BRCA1 gene is also known by other names, listed below.

What is the normal function of the BRCA1 gene?

The BRCA1 gene provides instructions for making a protein that acts as a tumor suppressor. Tumor suppressor proteins help prevent cells from growing and dividing too rapidly or in an uncontrolled way.

The BRCA1 protein is involved in repairing damaged DNA. In the nucleus of many types of normal cells, the BRCA1 protein interacts with several other proteins to mend breaks in DNA. These breaks can be caused by natural and medical radiation or other environmental exposures, and they also occur when chromosomes exchange genetic material in preparation for cell division. By helping to repair DNA, the BRCA1 protein plays a critical role in maintaining the stability of a cell's genetic information.

Research suggests that the BRCA1 protein also regulates the activity of other genes and plays an essential role in embryonic development. To carry out these functions, the BRCA1 protein interacts with many other proteins, including other tumor suppressors and proteins that regulate cell division.

Does the BRCA1 gene share characteristics with other genes?

The BRCA1 gene belongs to a family of genes called RNF (RING-type zinc fingers).

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 BRCA1 gene related to health conditions?

breast cancer - increased risk from variations of the BRCA1 gene

Researchers have identified more than 1,800 mutations in the BRCA1 gene. Many of these mutations are associated with an increased risk of breast cancer in both men and women, as well as several other types of cancer. These mutations are present in every cell in the body and can be passed from one generation to the next. As a result, they are associated with cancers that cluster in families. However, not everyone who inherits a mutation in the BRCA1 gene will develop cancer. Other genetic, environmental, and lifestyle factors also contribute to a person's cancer risk.

Most BRCA1 gene mutations lead to the production of an abnormally short version of the BRCA1 protein or prevent any protein from being made from one copy of the gene. As a result, less of this protein is available to help repair damaged DNA or fix mutations that occur in other genes. As these defects accumulate, they can trigger cells to grow and divide uncontrollably to form a tumor.

ovarian cancer - increased risk from variations of the BRCA1 gene

Many of the same BRCA1 gene mutations that increase the risk of breast cancer (described above) also increase the risk of ovarian cancer. Families with these mutations are often said to be affected by hereditary breast and ovarian cancer syndrome. Women with BRCA1 gene mutations have a 35 to 60 percent chance of developing ovarian cancer in their lifetimes, as compared with 1.6 percent in the general population.

prostate cancer - increased risk from variations of the BRCA1 gene

At least five inherited BRCA1 gene mutations have been found to increase the risk of prostate cancer. These mutations likely reduce the BRCA1 protein's ability to repair DNA, allowing potentially damaging mutations to persist in various other genes. The accumulation of damaging mutations can lead to the out-of-control cell growth and division that can cause a tumor to develop. Men who carry a BRCA1 gene mutation that increases the risk of prostate cancer may also be at increased risk for other cancers.

other cancers - increased risk from variations of the BRCA1 gene

Inherited mutations in the BRCA1 gene also increase the risk of several other types of cancer, including pancreatic cancer and colon cancer. These mutations impair the ability of the BRCA1 protein to help repair damaged DNA. As defects accumulate in DNA, they can trigger cells to grow and divide without order to form a tumor. It is not clear why different individuals with BRCA1 mutations develop cancers in different organs. Environmental factors that affect specific organs may contribute to the development of cancers at particular sites.

Where is the BRCA1 gene located?

Cytogenetic Location: 17q21

Molecular Location on chromosome 17: base pairs 43,044,295 to 43,125,483

The BRCA1 gene is located on the long (q) arm of chromosome 17 at position 21.

The BRCA1 gene is located on the long (q) arm of chromosome 17 at position 21.

More precisely, the BRCA1 gene is located from base pair 43,044,295 to base pair 43,125,483 on chromosome 17.

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

Where can I find additional information about BRCA1?

You and your healthcare professional may find the following resources about BRCA1 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 BRCA1 gene or gene products?

  • BRCA1 gene
  • BRCC1
  • breast cancer 1, early onset
  • breast cancer 1, early onset gene
  • breast cancer 1 gene
  • breast cancer type 1 susceptibility gene
  • breast cancer type 1 susceptibility protein
  • IRIS
  • PPP1R53
  • PSCP
  • RNF53

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding BRCA1?

cancer ; cell ; cell division ; colon ; DNA ; embryonic ; gene ; hereditary ; inherited ; mutation ; nucleus ; ovarian ; pancreatic ; population ; prostate ; protein ; radiation ; susceptibility ; susceptibility gene ; syndrome ; tumor

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


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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: October 2015
Published: November 23, 2015