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Curing Inherited Blindness Genetically

Posted by Ilena Di Toro | Posted on February 11, 2020

Let’s say you bought a new car and you discovered that it is defective. Instead of going back to the dealer, there was a way to fix the defect in the car while you were using it. That’s right, you could be driving around town while under the hood, things are being fixed by the car itself.

That’s not as pie in the sky as it sounds, at least for some forms of inherited blindness. Researchers are studying both which gene is defective and how the defect affects vision. The idea is to fix the defective gene, so that vision is restored. One genetic therapy now in use is Luxturna. This was approved by the Food and Drug Administration (FDA) in December 2017 to treat patients who have a mutation in the RPE65 gene, which can lead to Leber’s congenital amaurosis. This is an eye condition that affects the retina and can lead to vision loss and possibly blindness. The therapy works by delivering a normal copy of the RPE65 gene to the cells of the retina. The cells then produce the protein that converts light to an electrical signal to the retina and in turn restores vision.

Luxturna has helped many people to see better. One person who was helped by this therapy is a 4-year-old boy from Oregon, named Caspian Soto. He has Leber’s congenital amaurosis and is the second person in the state of Oregon to receive the treatment. A modified virus was injected into Caspian’s eyes and improvement in his vision came about within two weeks. He and his parents visited a museum and Caspian pointed out a plane’s blinking lights in the night sky, which was something he was not able to do before.

Still, one size does not fit all when it comes to treatment. That’s where genetic testing and counseling comes in. My Retina Tracker ( https://www.myretinatracker.org ) is one tool developed by the Foundation Fighting Blindness along with Blueprint Genetics and InformedDNA. My Retina Tracker offers no-cost genetic testing and counseling to persons with a clinical diagnosis of an inherited retinal disease. The goal is to test over 20,000 persons with an inherited retinal disease and that information will be used to help in the development of treatments and access subjects for clinical trials.

Of course, before you can get to the treatment you have to know what is going wrong in the first place. A discovery was made at the Oregon Health & Science University that three rhesus macaques have a genetic mutation that leads to Bardet-Biedl Syndrome. Bardet-Biedl Syndrome is a genetic form of blindness where a person develops a blind spot in childhood which over time develops into tunnel vision. In addition to impaired vision, Bardet-Biedl Syndrome is also associated with kidney problems, obesity and an extra finger next to the pinky. What makes the discovery of the rhesus macaques with this genetic mutation so important is that having a naturally occurring animal model will help in finding treatments and ultimately a cure for Bardet-Biedl, as well as other related eye conditions.

Researchers in genetic blindness aren’t just following one path to one discovery. They are utilizing multiple pathways to see what can be done to improve outcomes for people with these conditions.

Sources:

https://www.fightingblindness.org/research/to-treat-an-inherited-retinal-disease-it-s-good-to-know-exactly-what-s-wrong-with-the-gene-5045

https://www.fda.gov/news-events/press-announcements/fda-approves-novel-gene-therapy-treat-patients-rare-form-inherited-vision-loss

https://news.ohsu.edu/2018/10/16/releases-20181015-6723986

https://news.ohsu.edu/2019/10/25/discovery-in-monkeys-could-lead-to-treatment-for-blindness-causing-syndrome?fbclid=IwAR31UCQ7f2E7XMki9KgdYdm29t5lRR1gFjSbV39dOs7PdmCIfaO7oH2iWTA

https://rarediseases.info.nih.gov/diseases/181/stargardt-disease

https://rarediseases.info.nih.gov/diseases/6866/bardet-biedl-syndrome

https://www.fightingblindness.org/news/blueprint-genetics-informeddna-and-the-foundation-fighting-blindness-launch-an-open-access-program-for-patients-with-inherited-retinal-disease-in-the-36

https://www.fightingblindness.org/research/stargardt-disease-research-advances-6

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