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ODs’ role will increase in personalized medicine
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Arguably, the Human Genome Project is the most ambitious endeavor in the history of modern medicine. Not only has it provided us with an intricate genetic “road map,” but it has also given us a much better understanding of the link between genetics and disease.
In fact, the Human Genome Project (HGP) goes far beyond helping us locate the “address” of gene mutation(s) in a variety of disease processes. It also provides a better understanding of the mutation – and involved components – as it relates to the actual pathophysiology of the disease process in question. In short, we are learning more about the “occupants” that inhabit a specific genetic address and how their behavior influences the phenotypic expression of disease.
This concept is especially evident in age-related macular degeneration. We have long known that while age is the predominant risk factor for AMD, there is also a genetic component. The HGP has identified a variety of single nucleotide polymorphism (SNP) variations as genetic markers for AMD. As Michael J. Tolentino, MD, points out in this month’s Primary Care Optometry News, SNPs are found in a variety of gene locations associated with the complement pathway.
For me this has been an interesting, albeit somewhat unexpected, finding, as I generally think of the complement system as a key player in immune reactions. After all, isn’t the complement system a variety of proteins that regulate our immune system’s response to perceived threats? What could this possibly have to do with AMD?
Consistent with this theory is that drusen are rich in complement system byproducts. At the risk of over simplifying things, it appears certain genetic mutations result in rogue complement factors, which, in turn, drives the pathophysiology of AMD. In other words, bad occupants residing at a specific genetic address lead to the macula’s demise.
These revelations are certain to assist in developing more effective AMD treatments. Following the genetic road map to a specific locale and studying how those who live there behave enables us to devise more personalized treatment protocols.
For instance, if mutated complement factor H is responsible for AMD, we can specifically target treatments toward “correcting the behavior” of this factor. As Len V. Hua, OD, PhD, FAAO, points out in this issue, we will also be better at predicting for whom a specific treatment is indicated. While the discipline of pharmacogenomics is just emerging, it is certainly laying the foundation for personalized medicine.
As optometrists it is imperative we stay abreast of developments in genetic eye research. Right now, for our patients at risk for AMD we continue to emphasize lifestyle modification, diet, supplements and careful observation. However, as personalized medicine evolves we will play an increasingly important role in patient counseling as well as selecting treatment options.