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DNA Testing

From Bloodstream to Mainstream

The Merriam-Webster definition of identity is “the distinguishing character or personality of an individual.” But better understanding biological identity has, for a growing number of people, become a part of understanding their social identity.

DNA testing itself has run a colorful course - from late-night television paternity tests to high-profile crime scene evaluations, and from tracking human migration patterns to cluing in to your canine companion’s breed composition. These tests work by identifying and comparing fragments of DNA that are known to be associated with specific inherited conditions, features, or ethnicities. Until recently, genetic testing has predominantly been handled by the professional medical community. Now, with the advent of direct-to-consumer testing kits, anyone can, for a variety of reasons, unlock pieces of their biological passport. As research and accessibility have grown, the number of companies offering testing has exploded. Deciding which test to take depends on the piece of the spiral-helix story you hope to unravel. 

Most direct-to-consumer tests are not intended to provide actionable medical guidance, and cannot replace the valuable insight of trained medical professionals. When testing is performed by professional genetic counselors, people with a hereditary predisposition for disease can take steps toward prevention and mitigation of cancer, heart or neurological disorders, and more. However, if you’re curious to know more about your ancestral make-up, carrier status of well-known diseases, or whether your muscle composition is likely that of a sprinter or endurance athlete, at-home testing is an easy and inexpensive option. 

The DNA testing process is simple and pain-free. Kits typically include a vial used to collect a small saliva sample, and a pre-paid box in which to return the sample. Analysis can take up to 12 weeks, and to see results, companies require registration on their website. Using direct-to-consumer kits has its risks. One major criticism of at-home genetic testing is that companies are gathering massive amounts of consumer health data, and therein lies a potential breach of privacy if databases are hacked or sold. There are also possible psychological effects of uncovering otherwise unknown family histories or diseases.

For those interested in understanding their genealogy, Ancestry DNA is currently the highest rated option. Backed by a popular genealogy website that is home to billions of genealogy records, this test compares sections of the submitted DNA to that of people of a known origin, and analyzes the percentage of similarities. This type of information may not be surprising for those who have completed a family history, or done some genealogical research. Regardless, it can be an insightful learning experience, and cue further collaboration on family tree research. Reports from this test include a color-coded map and a pie chart of ethnic composition, and a platform to easily connect with users who, based on the genetic information, are likely to be related.

Another popular testing service is FDA-approved and Google-backed 23andMe. “Wellness reports” include information such as likelihood of lactose intolerance, ability to enter deep sleep, and alcohol flush reaction. Though it’s not intended to replace medical advice, information on wellness markers may solidify some health-related suspicions. The “trait report” is purely for fun, and with insights like cleft chin or toe length ratio, this section of the report is mainly used to teach the ways in which genetics influence your appearance. 23andMe will also tell you how rare these features are based on their customer pool.

The “carrier report” is intended to help consumers understand any genetic variants they may have a chance of passing down to their children. Reported-upon conditions include cystic fibrosis, sickle cell anemia, hereditary hearing loss, and many more. Again, this information is not intended to diagnose any conditions, or to be used as a guarantee to consumers or their offspring that they are not susceptible to the listed diseases. Instead, it can be a springboard for further medical evaluation and diagnosis.

Color Genomics, another Google-backed service, is a new at-home genetic test for mutations associated with 30 cancer genes. Color must be ordered by your physician, but “[it] does test the same genes we otherwise would in a clinical setting for hereditary cancer syndromes. They’re just designed to do it cheaper, and be available for anybody - so for example, people that I see who don’t meet [National Comprehensive Cancer Network] criteria but still really want testing,” says Elena Strait, genetic counselor at Penrose Cancer Center.

For those who currently have, or whose direct family has, an inheritable disease, such as cancer or neuromuscular disease, professional genetic counseling is advised. Getting professional help requires a detailed family history and risk assessment, and some patients may not meet testing criteria. 

Strait emphasized that there are limitations to these tests: a negative test result does not absolve patients from risk, and not all mutations or diseases are mapped. While only 10-15% of cancers are hereditary, catching cancer early vastly improves treatability. “The ultimate goal is to avoid cancer, especially in those who haven’t had it yet, but inherited that risk factor.”