Seoul National University Hospital preclinical researchers partnered with Toolgen, a local genome engineering venture, to successfully correct a genetic mutation completely by delivering genetic materials to a mouse with Leber congenital amaurosis.
What is Leber Congenital Amaurosis?
Leber congenital amaurosis is a common congenital retinal disease caused by mutations in genes related to visual function such as RPE (retinal pigment epithelium), 65, CEP (congenital erythropoietic porphyria) 290. Leber congenital amaurosis can result from mutations in at least 14 genes, all of which are necessary for normal vision. These genes play a variety of roles in the development and function of the retina. For example, some of the genes associated with this disorder are necessary for the normal development of light-detecting cells called photoreceptors. Other genes are involved in phototransduction, the process by which light entering the eye is converted into electrical signals that are transmitted to the brain. Still, other genes play a role in the function of cilia, which are microscopic finger-like projections that stick out from the surface of many types of cells. Cilia are necessary for the perception of several types of sensory input, including vision. Leber congenital amaurosis occurs in 2 to 3 per 100,000 newborns. It is one of the most common causes of blindness in children.
The research team was led by Professor Kim Jung-hoon at SNUH, who injected the adeno-associated virus vector carrying a CRISPR scissor and the normal RPE65 gene into the subretinal space of rd (retinal degeneration) 12 mice carrying the mutant RPE65 gene as reported in Korea Biomedical Review.
Consequently, the healthy RPE65 gene protein synthesized into the retinal pigment epithelial cells of the rf 12 mice. Thereafter six weeks and seven months post-treatment in two retinal electrocardiograms the visual response of rf12 mice improved by 20% of normal mice while also bringing back the thickness of the retinal nerve layer—truly an exceptional accomplishment. In this study, the team showed that the mutant gene could be completely corrected using the CRISPR scissors technology. A possibility has been introduced to the more fundamental treatment of congenital diseases, including Leber congenital amaurosis. Dr. Kim believes that this research “will become the cornerstone for the development of future clinical trials.”
Professor Kim Jung-hoon, Seoul National University Hospital
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