On Apr. 5, 2023, researchers at Oregon Health & Science University’s OHSU Casey Eye Institue announced that gene therapy had allowed the teen to see snowflakes for the first time. Paul Yang, M.D., Ph.D., an associate professor of ophthalmology in the OHSU School of Medicine who led the universityﾒs involvement in the trial.

For most, seeing snow is a normal winter occurrence. But for Aiden Moore-Van De Rostyne — who has a gene mutation that has significantly impaired her vision since birth — this was a first. Caught by surprise, Eliza quickly grabbed her smartphone and asked Aiden to repeat herself, but this time on camera.

he moment was the result of Aiden’s participation in a clinical trial at Oregon Health & Science University. One of Aiden’s eyes received an experimental gene therapy treatment in April 2022 through a study that is sponsored by Atsena Therapeutics. The experimental treatment sends tiny, molecular machinery to the retina in the back of the eye, where the therapy is designed to deliver a working form of a gene that’s critical for vision.

Mutations in at least 20 genes are known to cause Leber congenital amaurosis, or LCA, a rare condition that causes about one out of 50,000 babies to either be born legally blind or lose most of their vision as children. In Aiden’s case, a GUCY2D gene mutation caused her to be born with this condition. Atsena’s ATSN-101 gene therapy delivers working copies of the GUYCY2D gene.

Aiden is among 15 people in the United States who are participating in the Phase I/II trial, an early clinical study that is evaluating the experimental treatment’s safety and efficacy. Early results released in October 2022 indicate participants like Aiden, who received the highest gene therapy dose, have experienced “meaningful improvements in vision” without any serious safety events related to the gene therapy.

Before the trial, Aiden could only identify the largest letter on the chart that patients read during eye exams. To identify a shape or letter on paper, Aiden would touch her nose to the sheet, leaving about a half-inch of space between the paper and her eyes. She could differentiate between light and dark, but very bright light or sunshine were overwhelming and prevented her from seeing anything.

After receiving the experimental treatment in one eye, Aiden said she could see more of her mom’s face. And her paraeducator noticed that Aiden was bumping into fewer obstacles at school. While Aiden didn’t describe these changes in detail, various tests for the trial show Aiden’s vision has improved, including being able to read more letters on the eye chart.