Inherited Gene Mutations
This section provides information on BRCA1, BRCA2 and other high-risk inherited gene mutations, and how they impact breast cancer risk.
Genes and inherited gene mutations
What are genes?
Every cell in your body has genes. Genes contain the blueprints (genetic code) for your body.
For example, genes contain the information that determines the color of your eyes. They also contain information that affects how the cells in your body grow, divide and die.
The information in your genes is passed on (inherited) from your mother and your father. And, you can pass this information on to your children (your daughters and your sons).
What are inherited gene mutations?
Some changes in the genetic code that affect the function of the gene are called mutations. Mutations are rare.
Just as with other information in genes, mutations can be passed on from a parent to a child.
You get half of your genes from your mother and half from your father. So, for example, if your mother has a BRCA1 gene mutation, there’s a 50 percent chance you will also have a BRCA1 mutation.
Inherited gene mutations may also be called germline mutations.
Inherited gene mutations and breast cancer risk
Inherited gene mutations known to increase the risk of breast cancer are rare in the general population.
In the U.S., 5-10 percent of breast cancers are related to a known inherited gene mutation [4,32].
BRCA1 and BRCA2 (BReast CAncer genes 1 and 2) are the most well-known genes linked to breast cancer risk.
Everyone has these genes. Some people have an inherited mutation in one or both genes that increases the risk of breast cancer.
Inherited mutations in the following genes also increase the risk of breast cancer [38]:
- ATM
- BARD1
- CDH1
- CHEK2
- NF1
- PALB2
- PTEN
- RAD51C
- RAD51D
- STK11
- TP53
Other genes are under study and may also play a role in breast cancer.
BRCA1, BRCA2 (BRCA1/2) and other inherited gene mutations can be passed to you from either parent and can affect the risk of cancers in both women and men.
Some inherited gene mutations slightly increase breast cancer risk, while others (such as BRCA1/2 mutations) greatly increase risk.
BRCA1 and BRCA2 inherited gene mutations
Like other inherited gene mutations, BRCA1 and BRCA2 (BRCA1/2) gene mutations are rare in the general population. In the U.S., about 1 in 400 people have a BRCA1/2 mutation [32].
People of all races and ethnicities can have BRCA1/2 inherited gene mutations. However, the proportion of people who have a BRCA1/2 gene mutation varies by ethnic group. Among Ashkenazi Jewish men and women, about 1 in 40 have a BRCA1/2 mutation [32].
Learn more about BRCA1/2 inherited gene mutations in women.
Learn more about BRCA1/2 inherited gene mutations in men.
BRCA1 and BRCA2 inherited gene mutations and cancer in women
Breast cancer
Women who have a BRCA1 or BRCA2 (BRCA1/2) inherited gene mutation have an increased risk of breast cancer [32-38].
Estimates of risk are different for women with BRCA1 gene mutations and those with BRCA2 mutations. By age 70, the chance of developing breast cancer is [3,32,34-37]:
- 50-65 percent for women who have a BRCA1 gene mutation
- 50-55 percent for women who have a BRCA2 gene mutation
- 7 percent for women in the general population
This means by age 70:
- In a group of 100 women with a BRCA1/2 gene mutation, 50-65 will get breast cancer
- In a group of 100 women without a BRCA1/2 gene mutation, about 7 will get breast cancer
These numbers are averages. The risk of breast cancer for any one woman with a BRCA1/2 gene mutation may fall outside this range.
Note these risks are not 100 percent. Many women with a BRCA1/2 mutation will never have breast cancer [33-35]. A combination of factors likely causes breast cancer. So, some women with a BRCA1/2 mutation will get breast cancer and many will not.
Ovarian cancer and other cancers
BRCA1 and BRCA2 inherited gene mutations increase a woman’s risk of ovarian cancer, pancreatic cancer and melanoma (BRCA2 mutations) [32,36,38].
BRCA1/2 mutations may also increase the risk of other cancers [32]. However, data are limited, and these topics are still under study.
Learn more about BRCA1/2 inherited gene mutations in women.
Learn about risk-reducing options for women at higher risk.
Learn about genetic testing.
| For a summary of research studies on BRCA1 and BRCA2 inherited gene mutations and cancer, visit the Breast Cancer Research Studies section. |
BRCA1 and BRCA2 inherited gene mutations and cancer in men
Men can also have BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations and may pass them on to their daughters and sons.
Men who have a BRCA2 gene mutation, and to a lesser degree, men who have a BRCA1 gene mutation, have an increased risk of breast cancer [32-33,35,38,194-196].
BRCA1/2 mutations also increase the risk of prostate cancer, pancreatic cancer and melanoma (BRCA2 mutations) [32-33,38,196].
Learn more about BRCA1/2 inherited gene mutations in men.
Learn more about breast cancer in men.
Learn about cancer screening for men with a BRCA1/2 inherited gene mutation.
Learn about genetic testing.
| For a summary of research studies on BRCA1 and BRCA2 inherited gene mutations and cancer, visit the Breast Cancer Research Studies section. |
Other inherited gene mutations
In addition to BRCA1 and BRCA2 (BRCA1/2) inherited gene mutations, other inherited gene mutations increase the risk of breast cancer. Some also increase the risk of other cancers.
These gene mutations are less common than BRCA1/2 gene mutations and there’s still much to learn about them.
Some of these gene mutations are linked to a high or moderate risk of breast cancer (similar to BRCA1/2 mutations). The lifetime risk of breast cancer is increased 20-49 percent for women with moderate-risk gene mutations and 50 percent or more for women with high-risk gene mutations.
The table below provides a summary of high-risk and moderate-risk inherited gene mutations. Some of these gene mutations have only recently been shown to increase the risk of breast cancer. Data on these mutations and their related cancer risks are still emerging and will likely change over time.
In general, having a mutation in any of these genes leads to special breast cancer screening recommendations.
Gene |
Lifetime risk of |
Additional cancers with increased risk |
ATM |
20-40% |
Pancreatic cancer and possibly, prostate cancer |
BARD1 |
20-25% |
None known |
BRCA1 |
50-65% |
Ovarian cancer, pancreatic cancer, prostate cancer |
BRCA2 |
50-55% |
Melanoma, ovarian cancer, pancreatic cancer, prostate cancer |
CDH1 |
40-60% |
Diffuse stomach cancer |
CHEK2 |
20-45% |
Colorectal cancer, prostate cancer |
NF1 |
40-60% |
Brain and spinal tumors, gastrointestinal stromal tumors, neurofibroma, optic glioma, sarcomas |
PALB2 |
30-60% |
Ovarian cancer, pancreatic cancer |
PTEN |
80-85% |
Colon cancer, endometrial cancer, thyroid cancer and possibly, kidney cancer |
RAD51C |
20% |
Ovarian cancer |
RAD51D |
20% |
Ovarian cancer |
STK11 |
30-55% |
Colorectal cancer, endometrial cancer, ovarian cancer, pancreatic cancer, stomach cancer |
TP53 |
50-55% |
Adrenocortical carcinoma, bone and soft tissue cancers (sarcomas), brain tumors, colon cancer, leukemia |
| * The age up to which lifetime risk was estimated varied among studies. Adapted from selected sources [32,38,197,203-204]. |
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Some gene mutations are related to certain breast cancers. For example, women who have a BRCA1 gene mutation tend to get breast cancers that are triple negative [32]. And, CDH1 gene mutations appear to be related more often to invasive lobular breast cancers than invasive ductal breast cancers [199].
Genetic testing
It’s now common for genetic testing to check for multiple high-risk and moderate-risk inherited gene mutations, including BRCA1/2 mutations. This is called expanded panel testing or multi-gene testing.
Because panel testing is still fairly new, the specific set of genes checked for mutations can vary from test to test.
Panel testing is only recommended for some people.
As with any genetic testing, panel testing should only be done in a medical setting after a detailed discussion of the risks and benefits with a genetic counselor or a trained doctor or nurse [38]. These trained health care providers can also help determine the best test (and lab), given the pattern of cancer in your family.
Learn more about expanded panel (multi-gene) testing.
Breast cancer screening
- Women with a BRCA1/2 inherited gene mutation have special breast cancer screening guidelines.
- Men with a BRCA1/2 inherited gene mutation have special cancer screening guidelines.
Guidelines for people with other high-risk gene mutations are less clear. As more is learned about these mutations, guidelines can become more personalized.
Learn more about special breast cancer guidelines for women with an inherited mutation in an ATM, BARD1, CDH1, CHEK2, NF1, PALB2, PTEN or TP53 gene.
Breast cancer risk reduction
There are special breast cancer risk reduction guidelines for women who have a BRCA1/2 inherited gene mutation.
Guidelines for women with other high-risk or moderate-risk gene mutations are less clear. As more is learned about these mutations, guidelines can become more personalized.
Learn more about risk reduction options for women at higher risk of breast cancer.
Talking about family health history with your health care provider
Your family history of breast cancer and other health conditions is important to discuss with your health care provider. This information helps them understand your risk of breast cancer.
My Family Health History Tool |
My Family Health History tool is a web-based tool that makes it easy for you to record and organize your family health history. It can help you gather information that’s useful as you talk with your family members, doctor or genetic counselor. |
Support for people with inherited gene mutations
Some support groups are tailored to people with BRCA1, BRCA2 or other high-risk inherited gene mutations and those with breast cancers related to inherited gene mutations.
Our Support section offers a list of resources to help find local and online support groups. For example, FORCE is an organization that provides online and telephone support and a resource guide for individuals and caregivers affected by hereditary breast, ovarian and other cancers.
Sharsheret offers online support for Jewish women affected by hereditary breast and/or ovarian cancer.
Susan G. Komen® Support Resources |
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Finding clinical trials for people with inherited gene mutations
Susan G. Komen® Breast Care Helpline |
If you or a loved one needs information or resources about clinical trials, call our Breast Care Helpline at 1-877 GO KOMEN (1-877- 465- 6636) or email clinicaltrialinfo@komen.org. Se habla español. |
BreastCancerTrials.org in collaboration with Komen offers a custom matching service to help find clinical trials on breast cancer risk reduction.
You can also visit the National Institutes of Health’s website to find clinical trials.
Learn more about clinical trials.
Updated 04/06/22
