It took 10 years and $3 billion to map the human genome for the first time. I ordered mine on the internet for $99, and will have the results before Labor Day.
One of the fascinating—and worrisome—consequences of the Human Genome Project’s success at sequencing every human DNA base pair is the opportunity we all now have to peer at our own genetic fingerprints. Considered science fiction only a decade ago when the project concluded, personal genotyping cost several thousand dollars until recently. Now, it can be ordered for less than a week’s worth of groceries. “Retail genomics” is a reality.
It’s being popularized by web sites like 23andMe.com (named for the 23 chromosome pairs in every human cell), where I ordered my genetic profile. They’re sending me a sample collection tube to spit in and mail back, then in a few weeks I’ll get a report on my DNA genotype. It’s technically not a full sequencing (as in the Human Genome Project), just a Cliffs Notes version that quantifies my predispositions for 250 conditions, including glaucoma and AMD, but also everything from Parkinson’s to atrial fibrillation to liver disease.
Needless to say, I’m a bit worried about the results. My great aunt has AMD, and is nearly blind from it. If the test shows I’m at an elevated risk for the disease, I can adjust my diet, start taking an AREDS vitamin and get eye exams more frequently—all the usual strategies. I also can, and probably will, panic.
It’s easy to look at an elevated genetic predisposition for a certain disease and assume the worst. In such cases, incomplete information is probably more troubling than none at all; such knowledge can become a lifelong burden. And yet, knowing one’s propensity for various diseases does allow for early intervention, family planning and other measures that justify the unease such revelations cause.
But the funny thing is, I didn’t even especially want the disease screening data; I ordered the test because it will provide my ethnicity breakdown and ancestral lineage (as more people sign up, your global familial connections are uncovered). But 23andMe doesn’t separate out its health screening and ancestry services. So, bear in mind that some of your patients will be learning potentially monumental things about their genetic health profile without even expecting it.
Mendelian Meddling
Has industry rushed into retail genomics without due concern for ethical issues and proper patient education? For the consumer-based services, perhaps. The genetic tests available to medical professionals are more nuanced in both the way they assess risk and how they present the results. And, they keep you as the gatekeeper of the data.
This month’s cover story (see “Genetics in Eye Care,” page 68) provides an excellent primer on key concepts in genetic testing and the prospects for gene therapy in heritable ocular diseases. But beyond the science, you’ll also need to orchestrate the delicate art of genetic counseling, working in concert with primary care physicians to assuage your patients’ fears and put the results in perspective.
Is our DNA our destiny? Those 23 telltale chromosome pairs will become ever more relevant to your patient care. The continual rise of genetics as an integral part of medical risk assessment dovetails nicely with another medical megatrend: the drive to encourage preventive measures rather than after-the-fact treatment. Optometrists do more routine eye disease screening than anybody, of course, so it’ll fall to you to incorporate genetic risk modeling into your practice.
Also in this issue, retina expert Jerome Sherman, OD, describes familial involvement of Stargardt disease presenting with a biomarker found via SD-OCT. The one-two punch of genetic testing and advanced imaging is beginning to transform screening, diagnosis and management. Expect more to come.
That’s a brave new world, and an incongruous one—with ODs now having to deftly shift gears from discussing single nucleotide polymorphisms to anti-reflective lens coatings. Talk about an expanded scope of practice! You’re going all the way to the molecular level.
As for me, when my results come back, I think I might just give the health risk data—sight unseen—to my PCP, so that she can advise me. Sometimes, ignorance is bliss.
