This blog post was written by Deniz Temelli, Business Analyst at TechAlliance.
Early last December, the Google-backed personal genetics company 23andMe was ordered to stop marketing and selling its Personal Genome Service by the FDA. You can read the details of why in my last blog post.
The fall out and debate surrounding this decision is clearly still in full swing. In addition to 23andMe, which lacked the appropriate regulatory approvals for their genetic tests, personal genetics company GeneLink has just been charged with false advertising by the US Federal Trade Commission as well.
Here’s how the science of genetic testing works
After collecting and sending in a sample of your DNA, usually from a cheek swab, the first step in any personal genetics test is to sequence the DNA. This means determining the precise order of A, T, G and C, the four nucleotides that make up DNA. Sequencing technology has advanced significantly in the past decade in terms of cost, time and quality. A string of DNA can now be sequenced with over 99% accuracy. Of course, when you are sequencing 1 million nucleotides, a 1% error rate means being wrong 10,000 times, but still, this is not the part that the FDA has issue with. It’s what comes next where the core of this debate lies.
Science has come a long way in its study of certain genes related to specific diseases. It is this body of knowledge that 23andMe uses to interpret an individual’s DNA sequence to provide potential risks for certain diseases. Despite this amount of research, scientists are unanimous in saying that these links are not certain and there are still a lot of unknowns.
Why these companies are in hot water
One major issue with current genetic tests is that there is no industry standard that outlines which specific genes should be tested for different diseases and what the average population risk is. Both of these factors are very important when you take an individual’s DNA, examine a specific part of it, and then attempt to draw conclusions on their personal risk in relation to the average population. A NY Times article showing one individual’s results from multiple testing companies highlights this issue as the individual was found to have drastically different risk estimates for the same disease. This lack of repeatable and standard testing strongly supports the FDA’s position.
Keeping it all in perspective
Finally, it’s important to keep the true impact of our genes on potential disease in perspective. The onset of disease is influenced by many factors like diet, exercise and our environment. It is believed that genetics actually plays a fairly small part.
A recent study showed that the addition of genetic information did not improve a doctor’s ability to predict disease risk in comparison to just looking at family history and lifestyle.
The results of genetic tests should be taken with a grain of salt and are likely not as concrete as companies like 23andMe market them to be.
It seems like everyone can agree on a common vision for genetic testing where personalized risk probabilities will dictate personalized preventions and treatments. However, without a solid understanding of the link between genes and disease, it seems like we may never realize that vision.
The FDA’s letter to 23andMe has really put a spotlight on this topic and it will be interesting to see the impact it will have on biotech start-ups moving forward. Stay tuned for part 3 in this blog series where I will look at 23andMe’s response as well as lessons biotech entrepreneurs can learn!
