Ground-breaking gene therapy helps boy with congenital vision loss

Dr. Flavio Rezende and Dr. Cynthia Qian Credit: CIUSSS de l'Est-de-l'Île-de-Montréal For the first time in Quebec, gene therapy is being used to reverse a rare disease caused by a genetic defect, and it's thanks to the tireless work of two Université de Montréal doctors. Eleven-year-old William has Leber's congenital amaurosis, a rare hereditary disease that affects the retina and causes vision impairment and even blindness. But there's hope for William: in May, he received an innovative new treatment that could permanently improve his vision and, if all goes well, slow or even stop the progression of the disease. William is the first person in Quebec to receive a gene therapy designed to inhibit a disease by correcting the underlying genetic defect. In William's case, the problem is a mutation in the RPE65 gene that prevents photoreceptors in his retina from properly converting light into electrical signals. The treatment was approved by Health Canada in 2020, and then by Quebec for coverage under its public health plan in 2022. The surgery needed to administer the gene therapy was performed by Cynthia Qian and Flavio Rezende, retinal surgeons at the Ophthalmology University Centre of Maisonneuve-Rosemont Hospital and clinical professors in UdeM's Department of Ophthalmology.