Updated: Oct 21
Today’s DNA tests replace the dusty piles of family documents used for genealogy in the past. These new tests are of course not intended to be medical in nature. Instead, testing provides a statistical estimate of 1) what portion of people’s DNA derives from various regions of the world, suggesting where their ancestors lived, and 2) the degrees of shared DNA among people who have used the same DNA testing service, suggesting that those with high degrees of shared DNA are likely relatives.
Many people interested in their family roots find this new medium fascinating and exciting. It’s important to realize that unwanted information may also surface. Some people learn that they were adopted or that their fathers are not whom they thought. Other people who have not even had DNA testing may become forced to address family issues they were not consenting to learn. Also, questions are arising over law enforcement’s right to use these databases to find perpetrators of crimes.
Companies that offer genealogy DNA testing sometimes give their customers their raw DNA sequence data. Sequence data does not by itself reveal medical information because sequence data must first be interpreted. Other companies that don’t do the sequencing themselves offer a way for consumers to upload their DNA sequence to receive some interpretation of the data. Therefore, consumers who are seeking only genealogy information could end up with the offer to learn about other information that may be medical in nature. High rates of both false positives and false negatives have been reported among the medical results, so relying on this data alone for medical decision-making may lead to errors in medical management.
Several genealogy companies also directly offer DNA testing for a range of medical conditions and health-related features. We will cover those tests in an upcoming post.
3. Kolata, Gina and Heather Murphy. “The Golden State Killer Is Tracked Through a Thicket of DNA, and Experts Shutter.” NYTimes.com, April 27, 2018.
4. Marcus, Amy Dockser. “Customers Handed Over Their DNA. The Company Let the FBI Take A Look.” WSJ.com, August 22, 2019.
5. Marcus, Amy Dockser, “DNA Testing Creates WRenching Dilemmas for the Family Historian.” WSJ.com, July 20, 2019.
8. Tandy-Connor, S. et al. False-positive results released by direct-to-consumer genetic tests highlight the importance of clinical confirmation testing for appropriate patient care. Genomics in Medicine, 2018. 20:1515-1521.
9. Esplin, E. et al. Limitations of direct-to-consumer genetic screening for HBOC: False negative, false positives and everything in between. [abstract] Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P4-03-06.