Consumer’s Guide to Genetic Testing

Google-owned company 23andMe is launching a new program called Exome 80x, where a select few individuals can receive a data readout of their genome at a very high accuracy for the price of $999. According to the company’s promotional web site the benefits include:

A person’s physical structure, their body’s chemical reactions and the expression of their genes are controlled by the proteins encoded in the exome. The vast majority of genetic diseases also hinge on variations in the exome. For these reasons, exome data may be useful for those exploring their personal sequence data.

And

In contrast, the exome sequencing pilot provides users with raw variant data for about 50 million bases of DNA, without reports. Over time, 23andMe will add a limited set of tools and content that utilize exome sequence data.

Instead of the report that 23andMe offers its current clientele, Exome80x will provide clients with the raw data consisting of a list of nucleotides. Think of it as the difference between reading the results of an opinion poll and seeing every responder’s individual answer. The web site says that this test is not for everyone. For example, if you are unsure what the difference is between an exon and intron, then you are probably not a good candidate for this test. (See the report in Forbes, here).

DNA has “active” chunks and “inactive” chunks known as exons and introns, respectively. The active chunks code for proteins while the inactive chunks have been dubbed “junk DNA” because of their apparent lack of function. The DNA is “read” by proteins that go over every letter (or sets of three letters) and translate those letters into an amino acid chain. The amino acids are strung together and form a protein, molecular machines that conduct cellular function.

So the question is, if I had $999, would I get the test? The answer is no, for the following reasons:

  • Introns are not inactive. Several articles have appeared in the literature over the past few years that indicate introns are actually important segments of DNA and are anything but inactive. Introns may not code for proteins directly, but they probably assist in regulation and folding. See The Myth of Junk DNA for a summary of recent literature on this issue. So, for $999, I’d like the whole kit and caboodle, please, not just exons.
  • A parts list probably will not be helpful. A read-out of raw data means that for $999 you receive a parts list without an instruction book. This doesn’t mean it is useless for everyone in every case. For example, Matthew Herper from Forbes reports on a child that was suffering from severe and unknown complications in his intestinal tract. The doctors sequenced his DNA as a last-ditch effort to try to understand his mysterious disease. In most cases, all a DNA test can tell the doctors is if a person has markers for some diseases (not all diseases are genetic, so this is limited to genetic disease), but does not necessarily offer a solution. In this child’s case, the doctors found that he had a rare mutation that they decided to try and treat with umbilical cord stem cells. The treatment seemed to have worked well. However, this is not the norm. So, while the DNA test was a good idea for this child, I don’t know that it is a necessary procedure for someone who is healthy.
  • Ethical implications of knowing your genetics: The guilt. In the story above, the mother of the boy carries a lot of guilt because the gene was passed to him from her. She has made the decision to not have any more children. Her decision to not have children is a personal one. Genetic probability is not the same thing as certainty, but obviously she does not want to risk putting another child through this disease. However, the guilt poses another ethical concern. I do not believe this is a burden that this woman must bear. For now, we are not responsible for passing “healthy” genes, and we are not culpable for passing “unhealthy” genes. Perhaps this poses a larger bioethical question: With the advent of genetic testing, will people be held responsible (or hold themselves responsible) for genetic mutations? This seems to be treading down a eugenic-type path and mind-set that should be carefully examined.
  • Ethical implications of knowing: The inevitability and helplessness. In the book, DNA, by James Watson (with Andrew Berry), they report on a woman named Nancy Wexler, who has been a pioneer in the search for the genetic markers of Huntington’s Disease. Huntington’s Disease is a genetic degenerative disease. Nancy’s mother and uncles died of Huntington’s Disease, which means that she and her sister have a 50-50 chance of dying from it. Usually death occurs before age 60, and after a severe physical and mental decline. Even though she helped find the genetic markers for the disease, Nancy would rather not know whether she has the marker or not until a cure can be found (DNA, page 324, 325).

DNA sequencing is not a bad thing, and it has illuminated many areas of research, although it has not been the panacea that was hoped for during the years of the Human Genome Project. There are times and cases where looking for a mutation might be helpful, and thankfully it is an option for those difficult cases where doctors are dealing with mutations that wreak havoc on the body. But DNA sequencing is probably not something that everyone needs on his or her medical file. The bottom line: This consumer guide says that for most of us, your $999 would better serve your future health if you used it to buy a 3-year gym membership.

Leave a Reply

Please Login to comment
  Subscribe  
Notify of