Race to a Cure Authors
- Feb 26, 2021

DTC Genetic Testing

What is direct-to-consumer genetic testing?

DTC is genetic testing that is bought by consumers from private companies without the involvement of health care professionals. It does not involve healthcare providers such as physicians or nurses, nor does it include include genetic counsellors. DTC genetic testing also involves genealogy testing, which is the testing of a persons genomes in order to determine lineage. This type of genetic testing provides low accuracy information compared with other consumers and interpretation of information does not take into account environmental factors or family history.

Photo is courtesy of Harvard Health

How does direct-to-consumer genetic testing work?

Companies use a sample of consumers DNA often in the form of saliva, which is then sent back to the company and analyzed.

23andMe

23andMe analyzes variations at specific positions in your genome. These variations are called SNPs (Single Nucleotide Polymorphisms) and have the potential to tell you about your traits—such as eye or hair colour—and certain health conditions. 23andMe is not designed to analyze for repeated, inserted, inverted, translocated or deleted segments of DNA. Rather, it is compared with their DNA databases and the DNA of people who actually live in that country/area.

Photo is courtesy of Business Insider

Ancestry DNA

Ancestry DNA uses DNA marker’s AKA SNP’s absence or presence to compare it to their ‘reference panel’ database. Reference panel consists of people's DNA with deep ancestral roots to the geographic location. Consumers with similar SNP’s to DNA in their reference panel will have a higher chance of having roots to that specific region. Can also compare DNA to reveal family members around the world and history of migration patterns of ancestors.

Photo is courtesy of CNET

What are some concerns about DTC testing?

Accuracy

Accuracy of results depend from company to company because they don’t share the same database, reference panel and process/algorithms of determining results.

23andme gives consumers their genealogy results as well as a prediction of its accuracy.

“With the Ancestry Composition Report, customers can view their ancestry percentages at 5 different confidence thresholds - 50% (default), 60%, 70%, 80%, and 90% (most conservative)”

Different companies also look at different variants to determine your results. Just because results say that you carry a variant for diseases like Alzheimer’s, that does not mean that you will actually develop Alzheimer’s. However, a regular customer would not know that information; therefore, there is an inaccuracy of interpretation of results. Only a geneticist or something with a strong background in genetics would be able to accurately interpret variants and how that relates to the person tested.

2018 study by Vanderbilt University researchers found that:

71% of companies used consumer information internally for purposes other than providing the results to consumers.
62% percent said they use data for development, while
78% said they provided genetic information to third parties in de-identified or aggregate forms without additional consumer consent.internal research and
Consumers may not know where their information goes which impacts their personal autonomy

Lack of Oversight and Inadequate Interpretation and Counseling

“ . . . some tests offered by DTC companies, such as those for addiction, fetal gender, and general nutrition, are not widely accepted in the scientific community. In addition, even if a test is credible and the lab proficient, receiving test results without adequate interpretation and counseling can cause more harm than good. There simply are no standards governing how much information and what type of information DTC companies must provide to consumers before and after testing, leaving each company to make these decisions for itself.”

An example of this situation was Dorothy Pomerantz. After receiving her results from 23andme, her results revealed that she had the BRCA1 gene; the gene for breast cancer. From there, she wasn’t didn’t know how to interpret that information and didn’t know what her next steps would be after receiving that dreaded news.

“There will be countless other women who, like me, are going to find out about their increased risk of breast cancer through an online report as opposed to sitting with a genetic counselor, which is how people find out when they do genetic testing through a healthcare professional.”