DTC genetic testing today
Contributor Ramtin Hakimjavdi
One thing you simply cannot escape as a science student in 2018 — in your lectures or even in your conversations with professors — is the mention of advancements in genetics research. Overwhelming gains in knowledge about gathering and interpreting genomic data are being made every day. And this fact is not to be taken lightly, especially as aspiring scientists and doctors. Even the mention of skills in bioinformatics, for example, will make the eyes of any researcher in biologically related disciplines light up. One interesting development in rapidly growing field is the emergence of direct-to-consumer (DTC) genetic testing and how it is forcing its way into the mainstream.
DTC genetic testing today
It is fascinating to observe the commercialization of the human genome. We live in a time where we can ship our DNA away to a laboratory and shortly thereafter get results that reveal important information about our lives. What kind of information? A brief scan of 23andme.com will give you a good idea. For the most basic option, an exploration of one’s ancestry, the site charges $99. For ancestry and health services, the price is $229. But perhaps you are really curious to know everything about your genetic background. Their premium service, offered for $749, will give you ancestry information, health information, and your whole-genome sequence data. Just click “add to cart”, enter your payment information, send a small sample of your saliva, and wait for your results in the mail.
Genetic testing has never been more accessible than it is today. But the idea of sampling someone’s DNA and analyzing it to test for specific genetic conditions (Down syndrome, cystic fibrosis, etc.) is nothing new. Since the 1950s, genetic testing services were available and often used by healthcare professionals to confirm a diagnosis or to propose a new one. However, DTC genetic testing, a service provided to the consumer without the involvement of a healthcare provider, is in its infancy and rapidly gaining popularity.
Standard genetic testing and DTC genetic testing
The difference between standard genetic testing administered in a clinical setting and DTC genetic testing is subtle but important. Consider the general procedure followed by each service. Both start by sending the DNA sample and end with the results being shared with the individual. What’s different is everything in between. In the clinic, a physician would first decide what test is needed, order the appropriate test, interpret the test results, and only then would the results be shared with the patient. Companies offering DTC genetic testing allow anyone to order the test online and receive the results in the mail, effectively eliminating the middleman. Unfortunately, the middleman in this case is a well-trained healthcare professional. There is no authority present for guidance in the interpretation of the results.
In treating a patient, a physician uses results from a genetic test as a tool to supplement the expertise developed through years of medical school and training. Similarly, a genetic counselor is specifically trained to aid in the interpretation of your genetic background. But a regular person lacks the experience needed to independently assess the significance of the sequence of A’s, T’s, G’s and C’s being presented to them. This is the main concern with DTC genetic testing as it makes its way into the mainstream.
Enter the private sector
The cost of whole genome sequencing has rapidly declined since the completion of the Human Genome Project in 2003. What would have costed nearly fifty million dollars back then has been reported to have fallen to $4,000 in 2015. This number is estimated to continue plummeting, trailing advances in genome-sequencing technologies, which show no signs of slowing down.
The corollary of these declining costs is increased opportunity in the realm of genetic testing. Cheaper genetic tests have led to a lower barrier of entry for private companies with an interest in taking advantage of this new market. As these services have evolved, genetic tests for a plethora of different uses have emerged. Initially, tests provided useful medical information. For example, results could reveal carrier status for single gene conditions, predict susceptibility to complex diseases, justify more vigilant surveillance of health, or be used for prenatal screening. DTC genetic testing companies extended these possibilities by providing tests serving more trivial purposes, such as exploring one’s ancestry (as seen with 23andMe) or predicting one’s future athletic performance.
Certainly, the proper interpretation of the code written in this four-letter alphabet opens the possibility for amazing advances in healthcare and medicine. But with DTC genetic testing, it is the way that the service is marketed, how the information is presented, and the overall lack of genetic counseling that is cause for concern. Potential customers should be encouraged to think carefully before opting in. Given the complexity of the human genome, and the expertise required to accurately interpret the results from a genetic test, guidance from a healthcare professional should be inextricably linked to the entire process.
How access to your own genetic information can be dangerous
Turning to the genetic code for guidance in assessing your health can be tempting. But when seeking information about your susceptibility to disease or other potentially life-threatening conditions, desperation can often cloud judgement. It is important to recognize that our ability to derive meaning from these tests is somewhat lagging behind the rapid advances in genetic testing technology. In today’s “Information Age”, obtaining molecular sequence data is no longer the limiting factor. It is our ability to accurately interpret these data that needs refinement.
As it currently stands, once an individual’s genome is sequenced a genome-wide association study (GWAS) is performed. Essentially, your unique genotype is compared to the entire population in search of markers which, over time, have become associated with certain traits. Current understanding of genetic test results largely relies on making statistical associations between specific markers in the DNA and particular traits of interest (e.g., susceptibility to a certain disease). It is not as simple as looking at a sequence of someone’s DNA and concluding with 100% certainty that they have a certain condition or trait.
An unfortunate trend is the emergence of false advertising in the marketing strategies of some companies offering these services. As research advances, and our understanding of the human genome grows, it is becoming increasingly possible to use genetic tests to reveal useful personal information. However, the extent to which one’s DNA can be used to predict specific qualities or traits is still very limited. This is the reality that is not communicated by DTC genetic testing companies selling the idea that their tests have the answer to all of life’s uncertainties.
One study evaluated the validity of genetic tests claiming to be able to identify children’s athletic talents and predict future sports performance. Several concerns about such services were outlined: the misrepresentation of the current level of knowledge as it relates to interpreting genetic information, the lack of clarity in the methodologies used, and the overall lack of genetic counselling. The study concluded that in the current state of knowledge, genetic testing cannot provide any meaningful information about a child’s athletic talents and is an overall poor predictor of future sports performance.
It is not difficult to imagine the harm that access to such genetic tests, in the absence of a healthcare professional, can have on the lives of consumers. Consider the service that predicts a child’s future success as an athlete. Misinterpretation of test results could have a profound effect on the path parents choose for their child’s future. What’s more concerning is the potential impact of genetic tests providing health services. Interpretation of these test results is likely to influence life-altering decisions, making input from a doctor all the more important.
The Future of DTC Genetic Testing
The current state of DTC genetic testing is strikingly similar to that of patent medicine in the United States in the late 19th century. Patent medicine commonly refers to the drugs sold over-the-counter to consumers in a time before the Food and Drug Act (FDA) was established. Often high in alcoholic content, these remedies were advertised to cure all illnesses and even extend life expectancy. There is an important lesson to draw from the history of patent medicine in the USA and how it ultimately shaped the pharmaceutical industry. Patent medicine was born in a time where very little regulation on the manufacturing and distribution of drugs existed. But as regulation was implemented and medical research advanced, discoveries of drugs capable of legitimately curing illnesses and treating disease began to emerge.
Similarly, in today’s landscape, there is little regulation on DTC genetic testing services and an insufficient use of genetic counseling to accompany these tests. This is not to say that there is no value in the advancement of genome sequencing technologies or continued research in genomics. There is certainly reason to be optimistic for the future of genetic testing. However, until more rigorous studies on the utility and validity of these DTC services have been conducted, a healthy level of skepticism is certainly advisable.