CJG Blog

Center for Jewish Genetics blog

Direct-to-Consumer Hereditary Cancer Risk Screening: What Our Community Needs to Know

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April 18, 2018

In spring of 2018, the Food and Drug Administration (FDA) granted approval for consumer genetics company 23andMe to include information about breast and ovarian cancer risk caused by three BRCA1/BRCA2 mutations more prevalent among Ashkenazi Jews than other populations in the report it provides to users of its ancestry and health service. The FDA made their decision after a review process that determined that 23andMe’s test and results met appropriate benchmarks for accuracy. However, as the FDA’s press release noted, these three mutations constitute less than 1% of known BRCA1/BRCA2 mutations, and the receipt of these test results without guidance from a physician or genetic counselor may place individuals at risk for other harms.

The Norton & Elaine Sarnoff Center for Jewish Genetics cautions regarding the use of direct-to-consumer (DTC) testing such as the 23andMe test to determine one’s personal risk for hereditary cancer. Those who consider using such tests, or who receive such test results, should understand these key points:

  1. The results given by these tests are extremely limited and potentially misleading. The three mutations identified in 23andMe’s test represent only a small fraction of more than 1,000 known cancer-related mutations in the BRCA1/BRCA2 genes. Additionally, this test does not provide any information about mutations in other genes that can dramatically increase a person’s cancer risk. While the three BRCA mutations included in the 23andMe test are the more prevalent variants found in Ashkenazi Jews, it is possible for a Jewish individual to have a different mutation in BRCA1/BRCA2 or in another gene that increases their risk for cancer. Individuals with a significant personal or family history of cancer should consult with a genetic counselor or healthcare provider about more comprehensive testing options, as a negative 23andMe result does not eliminate the possibility of a different genetic mutation.

  2. Those who receive positive test results without assistance from a genetic counselor or qualified physician are not likely to have adequate preparation to understand their risk or evaluate appropriate preventative measures.

  3. Those who receive negative test results may not understand their remaining risks for hereditary or non-hereditary cancer. Only about 10% of cancers are directly linked to mutations such as those found in the BRCA1/BRCA2 genes. Some cancer is familial, but most cancer (about 70%) is sporadic, with no directly traceable genetic or familial component. A negative test result alone says very little about an individual’s ultimate risk for cancer.

  4. In almost all cases, physicians and genetic counselors who see patients regarding DTC results will and should recommend that patients get more comprehensive testing.

For individuals who have concerns about their hereditary cancer risk, we recommend:

  • Meet with a genetic counselor, or with a physician or health care provider involved with cancer treatment and prevention.
  • Discuss with that professional your personal and family history of breast, ovarian, and other cancers, what testing results can and cannot reveal, and the options that exist if a test reveals a mutation that increases risk for cancer.

The Norton & Elaine Sarnoff Center for Jewish Genetics offers a wealth of resources for persons who want to learn more about their risk and options for testing, prevention, and early detection. These resources include information on our website, JewishGenetics.org, and community access to a genetic counselor who is available to speak with concerned community members, provide education, answer questions, and direct individuals to appropriate clinical resources. 

How We Can Use Our Heritage to Find a Cure for Parkinson’s Disease

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By Barbara Robinson, MD

I’ve inherited many cherished heirlooms and traditions from my family – my grandmother’s candlesticks, my mother’s opal pendant and a collection of holiday recipes. As a physician, I’m keenly aware of one more inheritance: my genes.

It’s in Our Blood

Studies show that Ashkenazi Jews can trace their ancestry to just 350 individuals, which has created genetic similarities so acute that, according to scientists, "everyone is a 30th cousin." 

With gene mutations passed from generation to generation, Ashkenazi Jews are more likely to carry genetic variants that increase risk of certain conditions, including Parkinson’s disease. This unique ancestry presents a treasure trove of data for researchers, and a powerful opportunity to improve the kind of disease mapping that can speed cures.

I don’t have Parkinson’s myself but am a daughter, daughter-in-law and sister to individuals diagnosed with the disease –  and I know too well the difficulty and frustration that Parkinson’s causes millions of people and their loved ones, especially since the disease has no cure. 

The More You Know

Given my family history and Ashkenazi Jewish descent, I wanted to know my genetic status. I learned that I carry mutations in both my LRRK2 and GBA1 genes, which are each associated with increased risk for Parkinson’s. My husband Jay also carries a mutation in the GBA1 gene.

So, we set out to do everything in our power to learn more about Parkinson’s and test therapies to stop its progression. Together, we enrolled in the Parkinson’s Progression Markers Initiative (PPMI), a study sponsored by The Michael J. Fox Foundation, to share our data and biosamples to help scientists learn more about this disease and, most importantly, speed research that may lead to cures.

It’s Up to Us

PPMI is looking for people of Ashkenazi Jewish descent who themselves have either Parkinson’s or Gaucher’s disease (given a GBA1 connection) or have a first-degree relative who does. PPMI is enrolling people with a mutation in the LRRK2 or GBA1 gene and provides free genetic testing and counseling.

Jay and I support the study by participating in imaging tests and clinical exams. We each contribute biosamples of blood and spinal fluid on an annual basis. We’ve made this commitment because we know the only way we’re going to fight this disease is with knowledge, and this kind of data is our best hope for unlocking the key to new therapies. If we’re not willing to volunteer that data, then nothing is ever going to change. I hope you’ll join us.

Take a short quiz at www.michaeljfox.org/genetics or call 888-830-6299 to learn more about the PPMI study.

Talk to your doctor to discuss if participation in medical research is right for you.

Dr. Barbara Robinson is an obstetrician-gynecologist who lives outside Chicago.



Affordable, Accessible Genetic Screening in Illinois

Our affordable, accessible carrier screening program uses advanced technology to provide comprehensive screening for Jewish and interfaith couples. Visit our Get Screened page to learn more and register.


Do You Know What's In Your Genes?

What is the most valuable gift you can give to your family? The gift of good health! There are many health conditions that run in families. Knowing your family health history can alert you to the potential risk for a variety of genetic disorders . Talk to your relatives for warning signs and assess your risk for hereditary cancers.

Did you know: Ashkenazi Jews are 10 TIMES more likely to have BRCA mutations, which significantly increases lifetime risks for hereditary cancers, so what does this heightened risk mean for you? Click here to learn more .