Advancements in Gene Therapy for Inherited Retinal Dystrophies
Being diagnosed with an inherited retinal dystrophy (IRD) can be devastating. These rare eye diseases lead to progressive vision loss and, in some cases, even blindness. At the Cleveland Clinic, we have seen a significant increase in the number of patients with IRDs over the years. From 327 patients in 2015, the number has risen to almost 800 in 2019. The reason behind this surge is our improved ability to diagnose and treat these conditions.
Advances in Genetic Testing
Over the past two decades, we have discovered around 300 genes associated with IRDs. Thanks to advancements in genetic testing technology, we can now identify gene mutations in over 70% of all cases. This is great news because once we know the specific genetic mutation causing the disease, we can often refer patients to appropriate clinical trials that may help improve or maintain their vision. Even if there are no available trials at the moment, the future holds promise with the potential for revolutionary new treatments through gene therapy.
Why Gene Therapy Holds Promise
In gene therapy, an abnormal gene is replaced with a normal one. The most common method involves using a virus vector, which is a virus without the disease-causing parts, to deliver a healthy gene into the cells. This procedure is performed through eye surgery by a physician. The hope is that the cells with the new functional gene will function properly.
The eye is an ideal candidate for gene therapy for a couple of reasons. Firstly, the retina is relatively easy to access compared to other parts of the body. Secondly, the eye is “immune privileged,” meaning its immune response is not as active as in other areas. This is crucial because when a virus vector with a normal gene is injected into the eye, we don’t want the immune response to become overactive.
Current Available Treatments
Currently, there is only one FDA-approved gene therapy for inherited retinal disorders called Luxturna. It was approved in 2017 and specifically targets individuals with IRD caused by mutations in the RPE65 gene. This gene mutation is associated with retinitis pigmentosa and Leber congenital amaurosis (LCA). Luxturna delivers a functional copy of the RPE65 gene to the retinal cells, allowing them to produce the normal protein responsible for converting light into electrical signals in the retina. This treatment helps slow down disease progression and vision loss.
Patients with these forms of IRD typically experience difficulty seeing at night, followed by the loss of peripheral and central vision. Clinical trials of Luxturna showed significant improvements in patients’ ability to navigate through a mobility maze, even in darker environments. There have been remarkable stories of children whose vision has been restored through this procedure.
Several other clinical trials are underway for different IRDs, such as X-linked retinitis pigmentosa, choroideremia, and achromatopsia. These trials show promise in halting vision loss and, in some cases, even improving vision.
Hope for People with IRDs
Gene therapy has the potential to revolutionize the treatment of inherited retinal disorders. Just a decade ago, patients with IRDs had limited options and were offered low-vision therapy. Now, with genetic testing, we can identify specific gene mutations and connect patients with gene therapy trials to replace the malfunctioning gene.
If you have an IRD, it is crucial to catch and treat the disease before it progresses too far. Genetic testing plays a vital role in early detection, and once completed, we can search for available clinical trials across the country. You can also stay updated on active and recruiting clinical trials in the United States and globally through https://clinicaltrials.gov.
Even if you don’t have a diagnosed IRD but have a family history of one, it is important to prioritize your eye health. If recommended by your physician or genetic counselor, undergo genetic testing to ensure you are not a carrier and encourage other family members to do the same. Early detection is key.
Looking Ahead: Cell Therapy
Looking further into the future, there is growing excitement surrounding cell therapy. This treatment involves replacing diseased retinal cells with stem cells that can develop into healthy ones. Although studies are still in the early stages, cell therapy holds promise not only for people with IRDs but also for those with other common retinal diseases like age-related macular degeneration.
The future has never looked brighter for individuals with IRDs. While we cannot promise 20/20 vision, we can offer hope through clinical trials that may improve their sight.
Photo: Freepik.com
