Genetic Testing for Macular Degeneration

8:00 PM

I attended a CE earlier this week and came away with knowledge of a great new service for optometrists and their patients.  Age Related Macular Degeneration is a potentially blinding condition that typically affects central vision in patients over the age of 60.  There is a large hereditary component (in addition to environmental factors), and since the conclusion of the Human Genome project, we now know a number of genes directly linked to the severe forms of the disease. Before I go into more detail I would like to add a disclaimer that I have not yet used this service, and I am in no way affiliated with them.  I do plan on possibly offering this genetic testing to my patients in the future; the results are actually very inspiring!

No blood tests needed, just a quick, easy cheek swab.
The Process
As an optometrist, all you need to do is sign up with the Macula Risk company (at no cost of course) and you will be sent packaging and sterile swabs to perform a cheek swipe for DNA sampling.  For any patient you want to genetically test, you would swab the inside of the cheek, package the swab in the provided sterile container, and FedEx the swab to the testing center in a prepaid envelope.  In 2 to 4 weeks, the company will have the DNA samples analyzed and sent you a full report as to the patient's risk factors.  You can schedule a 1-2 month follow-up visit after your initial sampling to discuss these results with the patient and set a plan for future management.  Like I said, I haven't tried this yet, but the process seems simple, easy, and free to the doctor and patient (as long as they have medical insurance).

What genes are being tested?
Age Related Macular degeneration can be linked to genes that control numerous ocular pathways.  Genes that control the Complement Cascade inflammatory response (CFH and Y402H genes specifically), genes that control cellular response to oxidative damage (like the ARMS2 gene), and genes found in mitochondrial DNA are all found to be linked to ARMD incidence at various rates.

ARMD is found in 10% of the population over age 60 and 25% of the population over age 75, so there are more and more patients being diagnosed with this disease every day with our aging baby boomer population.     The good news?  80% of patients diagnosed with early or dry ARMD will never have advanced vision loss. But that leaves 20% of patients that will develop devastating central vision destruction for the disease, and doctors have had few ways to predict which patients will belong to that 20%.  Unfortunately, the majority of these 20% of patients with severe or wet ARMD will not go to a doctor for treatment until they already have  permanent vision damage.  The goal of the Macula Risk genetic testing is to red flag that 20% of the ARMD population that will develop advanced disease when they still have great vision based on their genetic markers for the disease!

DRY ARMD photo courtest avclinic.com
WET ARMD photo rustoneye.com
The company sends you a print out of the patient's "Macula Risk score" based on their genetic profiles.  I'm not sure of the details, but if the patient's risk number is between 3 and 5 (with 5 being the highest) they are much more likely to develop advanced ARMD.  This signals the doctor to follow the patient more closely than just yearly exams, and the patient is also more educated to pursue lifestyle changes that can improve their ocular health (such as quitting smoking, eating more green leafy vegetables or adding vitamin anti-oxidant supplementation).  If the patient knows they are at a high risk, they are going to be much more likely to be compliant with regular exams and the disease processes can be caught earlier before vision is irreparably damaged.
Ocular Vitamins can be even more strongly recommended in younger patients  with drusen changes if their  genetic testing reveals higher risk factors.  Interestingly, even the presence of peripheral drusen has been found to genetically link to ARMD progression.


When would a genetic test for ARMD be warranted?


While we would all like to be able to do a screening of all patients with known family history, at this time the company can file medically with diagnoses of ARMD or retinal drusen (peripheral and macular drusen are both billable).  The company files to the patient's medical insurance directly for coverage, so the doctor does no billing and the patients will not be getting a bill.  At this time, there is no copay for the procedure.

I'm really looking forward to possibly implenting this genetic testing into my practice.  Please let me know if you have any opinions: if you have used this product before and if you would find it beneficial as a patient!


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