Last week, we discussed the role of genetic counselors in preparing the public to emotionally and intellectually handle the results of mail-in genetic tests. While such tests were recently only available to a select few, there are now more than a thousand being directly marketed to average citizens. To understand the nature of mail-in tests, with their confusing mix of problems and benefits, we will examine the case of one particular testing company that has been receiving a lot of media attention.
In 2003, Dr. John Kelsoe discovered a genetic indication of bipolar disorder. He was working as an academic researcher at University of California, San Diego, but he decided to take this discovery into the private sector. His entrepreneurial spirit resulted in Psynomics, a small but growing company that offers a mail-in test that can be ordered over the internet for less than $400. This test requires only a small amount of saliva deposited into a cup. An effective genetic test could be helpful because bipolar disorder can often be difficult to diagnose, and can present similarly to depression. If patients are given only antidepressants, it's possible for them to flip into manic episodes.
The bipolar test is simple to take, but it does not yield easy-to-understand results. Bipolar disorder is not fully understood, but the current consensus is that it is caused by a complex interactions of genes and environment. The Psynomics test does not even give a full picture of the genetic half of the equation. While it is true that having one of the GRK3 gene variations that Dr. Kelsoe identified might triple your chances of having bipolar disorder, these numbers can be deceiving. That variation shows up in only three percent of those diagnosed with bipolar disorder. This is three times higher than the one percent of the general population with the variation, but it is obviously not necessary or sufficient for bipolar disorder. The Psynomics website has many disclaimers, but it would be easy for customers to either wrongly take a negative result as an all-clear or a positive as an inescapable sentence. There is currently no FDA oversight to ensure the safety of customers.
One unique way that Psynomics avoids the problem of misinterpretation is its rule that results are sent only to doctors. The doctor then uses this information, along with observation about patient behavior, to make an informed diagnosis and discuss the risks. The field of genetic tests is new and largely unregulated, so it is very encouraging to see that at least one company recognizes the importance of sending the information to those who are trained to interpret it. Doctors have a better grasp of the statistical importance of genetic tests, and they should be able to explain to patients that these tests are just one helpful tool in the diagnostic toolkit.
The other unique thing about the bipolar test is that it is used primarily to make a current diagnosis, rather than predict future developments. Predicting the future is a much shakier enterprise.
Psynomics has been working to expand its stock of tests. Its newest offering is a test for suicidal reaction to antidepressants. Individuals have widely varying reactions to different drugs, and the current method of trial-and-error is unacceptably crude and dangerous. Hopefully, genetic tests will soon be able to guide the prescription process so that drug regimens can be specifically tailored to the individual. Academic research has contributed much to our understanding of the brain, but sometimes it takes capitalism to push theory into practice.
|