So Time magazine stated boldly on its January 1994 cover, claiming, “New breakthroughs can cure disease and save lives.”
So, how have we done? Where are we from a retinal perspective?
Without a doubt, we have covered a lot of ground. Over the last two decades, more than 200 distinct genes have been identified that, when mutated, can lead to retinal dystrophies. Spring boarding from this work, multiple ongoing trials are investigating various gene-based therapies to treat a range of monogenetic retinal diseases. The approach most likely to reach clinical application first, gene-based therapy for RPE65-associated Leber congenital amaurosis, also known as LCA2, has been submitted for regulatory review in the United States with approval anticipated for this year. See page 35, where Christine Kay, MD, explores this exciting space and compares ongoing investigations in inherited retinal disease.
We have also seen great progress on retinal diseases with more complex genetic underpinnings. We have learned that the risk of age-related macular degeneration is largely attributable to our genes, although it is a complex relationship involving more than 34 genetic loci. See page 26, where Steve Schwartz, MD, MBA, and Parth Shah bring us up to date on the pharmacogenetics of AMD and how this might impact our management recommendations.
But clearly, much more remains to be learned. The American Academy of Ophthalmology continues to recommend against routine genetic testing for complex genetic diseases including AMD. Why, and when might the AAO recommend otherwise? See page 31, where Karmen Trzupek, MS, a certified genetic counselor, beautifully explores the realities and challenges of genetic testing in your clinic.
As well highlighted in an excellent 2015 American Journal of Ophthalmology “Perspective,” gene therapy has been hailed as “five years away” from clinical application since the 1990s.1 As clinicians, it is our responsibility to educate patients about their options while providing hope of treatments yet to come.
However, this hope must be grounded in an understanding of the reality of current research. Fortunately, the promise of clinically ready and clinically valuable genetic testing, as well as gene-based therapies, appears to be closer than ever to reality. I hope the articles to follow bring you up to date on our current understanding of the genetics underlying many of the retinal diseases we manage.
1. Benjaminy S, Kowal SP, MacDonald IM, Bubela T. Communicating the promise for ocular gene therapies: Challenges and recommendations. Am J Ophthalmol. 2015;160:408-415.