3, not 3,000
The FDA cleared 23&Me to offer direct-to-consumer genetic testing. Clinicians may want to be cautious before suggesting it for their patients.
What are the benefits of the 23andMe health test?
23andMe and other ancestry tests have raised consumer awareness of DNA testing, and that’s a good thing. Also, a positive finding may encourage patients to engage with their healthcare providers to pursue appropriate screening or manage their health better.
What is the limitation with the 23andMe health test?
23&Me’s test has gaps. It excludes testing for some important genetic variants that cause disease, even for the diseases the company advertises. It's like only having a few pieces to a puzzle with thousands of pieces. For example:
1. >3000 variants in BRCA1/2 have an association with hereditary breast and ovarian cancer (HBOC) syndrome. The 23andMe test looks for three variants.
2. Other genes, such as TP53, ATM, and PALB2, also suggest an increased risk for breast cancer, among other cancers.
The same issue can be stated for other parts of 23&Me’s test, including pharmacogenetic testing.
Why did FDA clear 23&Me?
23&Me demonstrated that the three variants on its test do indeed have a clear and strong association with HBOC. The approach makes sense for an organization that has traditionally reviewed drugs and medical devices for safety and efficacy. However, this approach is not comprehensive for all causes of inherited disease.
Why is 23&Me designed for consumers but not for providers to order?
FDA requires 23&Me to include many disclaimers about ordering testing, one of which is not to use results for medical purposes. Most people will assume that if a health provider orders a test, it is intended for medical management.
What should providers do?
Labs are finding ways to make ordering genetic testing easier for both patients and their providers. As a first step, look for a lab that offers a panel of genes associated with the condition of interest, and be sure the lab is sequencing the genes with supplemental assays for variants that are not currently identified through sequencing. Ask the lab for sample reports and for a tour of their online results’ modules, if any. It may also be very helpful if the lab offers client service from genetics professionals certified in patient care, like genetic counselors or medical geneticists.
1. National Center for Biotechnology Information, ClinVar Database, accessed July 17, 2019.
2. “FDA authorizes, with special controls, direct-to-consumer test that reports three mutations in the BRCA breast cancer genes” FDA Press Release, March 6, 2018. Accessed July 17, 2019 https://www.fda.gov/news-events/press-announcements/fda-authorizes-special-controls-direct-consumer-test-reports-three-mutations-brca-breast-cancer