OCT 14, 2022 9:47 AM PDT

Experimental Gene Therapy Restores Night Vision in Blind Patients

WRITTEN BY: Annie Lennon

Adults with a hereditary form of childhood-onset blindness experienced dramatic improvements in night vision within days of receiving an experimental gene therapy. The corresponding study was published in iScience

The patients had Leber Congenital Amaurosis (LCA), a rare eye disorder that primarily affects the retina. Around 1 in 40,000 newborns are affected by the condition. Symptoms typically begin from birth to 23 months, and include severe visual impairment, eye discomfort in bright light, and involuntary movement of the eyes. 

Multiple gene variants are thought to cause the disease, however, mutations in GUCY2D- a gene that encodes a protein needed in retinal photoreceptor cells to convert light into neural signals- cause up to 20% of cases.

Previous imaging studies have found that patients with this form of LCA often have relatively preserved photoreceptor cells- especially in areas with a high density of rod cells, needed for vision in low-light settings. The researchers thus hypothesized that these rod cells could enable vision again, if functional GUCY2D genes were present. 

In the current study, researchers tested their theory on a 19-year-old man and a 32-year-old woman. Both patients had some, although greatly impaired, visual function in daylight. However, at night, they were effectively blind and had a light sensitivity 10,000 to 100,000 times less than normal. 

The researchers administered adeno-associate virus (AAV) gene therapy to both patients. The therapy worked by carrying a healthy version of the GUCY2D gene to the retina of one eye for each patient. Within eight days, the researchers noted that night vision in the patients’ treated eyes improved 1000-fold. Several night vision tests demonstrated that the patients’ night vision neared that of those with healthy rod vision. 

The researchers concluded that GUCY2D gene therapy can restore rod-based photoreceptor functionality and that patients with LCA from a defective GUCY2D variant may benefit most from the therapy. They also noted that their findings highlight the fact that the vision apparatus in some with severe vision loss may be largely intact, and that the addition of a missing protein may be sufficient to kickstart vision immediately. 

The AAV therapy trial is ongoing, and registered at clinicaltrials.gov as trial NCT03920007.

Sources: iScience, Penn Medicine News

 

About the Author
Other
Annie Lennon is a writer whose work also appears in Medical News Today, Psych Central, Psychology Today, and other outlets. When she's not writing, she is COO of Xeurix, an HR startup that assesses jobfit from gamified workplace simulations.
You May Also Like
DEC 02, 2022
Genetics & Genomics
Tips on Establishing a Reliable Cell Free DNA Workflow
Tips on Establishing a Reliable Cell Free DNA Workflow
Ever since its first discovery in 1948, circulating cell-free DNA (cfDNA) has captured the attention and imagination of ...
NOV 30, 2022
Drug Discovery & Development
Saying "Bye" to UTI E. Coli
Saying "Bye" to UTI E. Coli
In the arms race between animal and bacteria, endogenous antimicrobial peptides (AMPs) are our body’s way of defen ...
DEC 06, 2022
Drug Discovery & Development
Cannabinoids Fail to Improve Measures of Pain Intensity Above Placebo
Cannabinoids Fail to Improve Measures of Pain Intensity Above Placebo
Cannabinoids are commonly prescribed for conditions such as back and cancer pain. However, evidence that it offers an an ...
DEC 09, 2022
Cannabis Sciences
What are fast acting edibles, and how do they work?
What are fast acting edibles, and how do they work?
Fast acting edibles are one of the newest and most popular products on the market. Here's what's behind the fast acting ...
JAN 12, 2023
Drug Discovery & Development
Blood Pressure Drug Could Treat PTSD in Veterans
Blood Pressure Drug Could Treat PTSD in Veterans
A drug used to treat blood pressure and ADHD may be able to mitigate PTSD symptoms. The corresponding study was publishe ...
JAN 22, 2023
Neuroscience
Research Study Explores the Mysterious Causes of Pediatric Epilepsy
Research Study Explores the Mysterious Causes of Pediatric Epilepsy
Childhood epilepsy affects roughly 4% of the pediatric population, and there are many different types of epilepsy and se ...
Loading Comments...