Understanding the 1 in 40: Jewish BRCA Risk & Prevention

If you have Ashkenazi Jewish ancestry, there is one statistic worth knowing: 1 in 40. That is the estimated rate at which people of Ashkenazi Jewish descent carry a mutation in the BRCA1 or BRCA2 gene. These are genes that protect against DNA damage, and when mutations occur in these genes, this dramatically increases the risk of breast, ovarian, prostate, and pancreatic cancers.¹ By comparison, the carrier rate in the general population is approximately 1 in 400.¹ This guide explains what that means for you, why Jewish ancestry matters, and what you can do to learn about and potentially mitigate your personal risk.

What Are BRCA1 and BRCA2?

Everyone has BRCA1 and BRCA2 genes. In their normal functioning state, they are tumor suppressor genes, which means they help repair damaged DNA and prevent cells from growing in an uncontrolled way.² When a person inherits a harmful mutation in one of these genes, that protective function is impaired, and the risk of developing certain cancers increases dramatically.

BRCA mutations follow an autosomal dominant inheritance pattern, meaning you only need to inherit one mutated copy, from either parent, for your cancer risk to be elevated. Each child of a carrier has a 50% chance of inheriting the mutation from the affected parent.²

It’s important to note that many people with a BRCA mutation have no known personal or family history of cancer.¹ Waiting for a cancer diagnosis or a family health event to prompt testing can mean missing the window for the most effective prevention.

Why Are BRCA Mutations More Common in Jewish People?

The elevated BRCA carrier rate in the Ashkenazi Jewish population is the result of the same phenomenon that drives elevated rates of other Jewish genetic diseases. This is called the founder effect. The modern Ashkenazi Jewish population descends from a relatively small group of ancestors, and three specific BRCA mutations became concentrated across generations:¹

• BRCA1 185delAG²
• BRCA1 5382insC²
• BRCA2 6174delT²

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Together, these three mutations account for the overwhelming majority of BRCA mutations found in people of Ashkenazi Jewish descent.⁴ As a result, approximately 1 in 40 Ashkenazi Jews carries one of these mutations, which is approximately 10 times the rate seen in the general population.¹

Sephardic and Mizrahi Jewish individuals also carry elevated BRCA rates, though at lower frequencies and with different mutations. If you have any Jewish ancestry, BRCA testing is worth discussing with a genetic counselor or your physician.

What Cancer Risks Come with a BRCA Mutation?

For Women

Women who carry a BRCA1 or BRCA2 mutation face significantly elevated lifetime risks of breast and ovarian cancer compared to the general population.⁵

• Breast cancer: up to 72% lifetime risk for BRCA1 carriers; up to 69% for BRCA2 carriers, compared to about 13% in the general population.²
• Ovarian cancer: 35–70% lifetime risk for BRCA1 carriers; 10–30% for BRCA2 carriers, compared to about 1–2% in the general population.^6,5

BRCA-related breast cancers tend to develop at younger ages and may be more aggressive than sporadic breast cancers, making early and proactive screening especially important.⁵

For Men

BRCA mutations affect men too, and their risks are often underestimated. Men who carry a BRCA mutation face elevated risks of:⁴

• Prostate cancer: up to 25% lifetime risk (BRCA2 carriers are at particularly elevated risk).⁴
• Male breast cancer: up to 7% lifetime risk with BRCA2 (compared to about 0.1% in the general population).²
• Pancreatic cancer: elevated risk for both BRCA1 and BRCA2 carriers.²

Because BRCA mutations are inherited, a man who carries a mutation has a 50% chance of passing it to each of his children, making testing important for the whole family.

What Can You Do If You Test Positive?

A positive BRCA result is not a cancer diagnosis. Rather, it is valuable information that enables action. Carriers have real, evidence-based options to reduce their cancer risk and catch cancer early when it is most treatable.³

Enhanced Cancer Screening

For women with BRCA mutations, guidelines recommend starting breast cancer screening earlier and using more sensitive imaging.⁵ Recommendations include: 

• Annual breast MRI starting at age 25 (or earlier based on family history).⁵
• Annual mammography typically beginning at age 30, often alternating with MRI every 6 months.⁵
• Clinical breast exams every 6–12 months starting at age 25.⁵

Recent NCI research confirms that MRI surveillance significantly reduces mortality from breast cancer in BRCA mutation carriers.⁷

Risk-Reducing Surgery

For women who want to substantially lower their cancer risk, there are two surgical options that may be an option:⁵

• Prophylactic (preventive) bilateral mastectomy: removal of both breasts before cancer develops, which reduces breast cancer risk by more than 90%.²
• Risk-reducing salpingo-oophorectomy (RRSO): removal of the ovaries and fallopian tubes, which reduces ovarian cancer risk by approximately 80% and also lowers breast cancer risk in premenopausal women.²

These are deeply personal decisions. Many women choose enhanced surveillance over surgery, and both approaches are valid. A genetic counselor and oncology team can help you weigh the options based on your specific mutation, age, and family planning goals.

Chemoprevention

Medications such as tamoxifen and raloxifene are FDA-approved to reduce breast cancer risk in high-risk women.² While it must be acknowledged that data specifically in BRCA carriers is limited, these medications may be a consideration as part of a personalized risk management plan discussed with your physician.³

Screening for Men

Men with BRCA mutations should work with their physician to develop a personalized screening plan. Guidelines generally recommend earlier and more frequent prostate cancer screening, as well as clinical breast exams, for male BRCA carriers.²

How to Get Tested

BRCA testing can be done with a simple saliva test or blood draw. The hereditary cancer screening analyzes BRCA1, BRCA2, and 61 additional hereditary cancer genes from home with a saliva test – no doctor appointment required.

Every jscreen hereditary cancer screening  includes a telehealth appointment with a certified genetic counselor at no additional charge. If you test positive, a personalized care plan is developed and a care navigator helps coordinate next steps. The majority of customers who pursue hereditary cancer testing pay nothing out-of-pocket through a combination of insurance coverage and financial assistance.

What About Your Family?

Because BRCA mutations are inherited, a positive result has implications beyond just the individual who tested. Each first-degree relative (parents, siblings, and children) has a 50% chance of carrying the same mutation.²

The American College of Obstetricians and Gynecologists recommends that carriers share their results with relatives and encourage family members to pursue their own genetic counseling and testing.² Learning about a family mutation early, before a cancer diagnosis, gives relatives opportunities for proactive prevention.

For families actively planning to have children, it is also worth noting that BRCA mutations can be detected in embryos through preimplantation genetic testing (PGT), giving carrier couples the option to select unaffected embryos for transfer to the uterus during IVF.

Knowledge Is the First Step

A BRCA mutation does not have to mean a cancer diagnosis. For the many Ashkenazi Jewish individuals who carry one of the three founder mutations, knowing your status is the single most powerful thing you can do to protect your health. Monitoring and prevention save lives, and it all starts with a simple test. Order your hereditary cancer test today to get started. 

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Related Reading 

• BRCA Gene Inheritance Explained: Making Testing Decisions for Your Family
• Ashkenazi Jewish Genetic Diseases: A Complete Guide to Testing
• From Screening to Success: Navigating Jewish Family Planning
• Hereditary Cancer Screen: What's Included and Why It Matters
• Genetic Counseling: What to Expect from Your Appointment

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References

1. Garber J. What's the connection between BRCA and Ashkenazi Jewish ancestry? Dana-Farber Cancer Institute. June 26, 2023. https://blog.dana-farber.org/insight/2023/06/whats-the-connection-between-brca-and-ashkenazi-jewish-ancestry/

2. National Cancer Institute. BRCA gene changes: cancer risk and genetic testing. Updated November 25, 2024. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet

3. Basser Center for BRCA, University of Pennsylvania. Managing Cancer Risk. Updated 2024. https://www.basser.org/managing-cancer-risk

4. Basser Center for BRCA, University of Pennsylvania. BRCA in the Jewish Population. Updated 2024. https://www.basser.org/brca/brca-ashkenazi-jewish-community

5. Basser Center for BRCA, University of Pennsylvania. BRCA in Women. Updated 2024. https://www.basser.org/brca/brca-women

6. American Cancer Society. Ovarian cancer risk factors. Updated 2024. https://www.cancer.org/cancer/types/ovarian-cancer/causes-risks-prevention/risk-factors.html

7. National Cancer Institute. MRI, surgery reduce cancer deaths in women with BRCA changes. Published April 15, 2024. https://www.cancer.gov/news-events/cancer-currents-blog/2024/brca-breast-ovarian-cancer-mri-surgery-fewer-deaths

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