CRISPR-Mediated Gene Editing Tool Development for Patients with Usher Syndrome Type II

Usher syndrome, a rare genetic disease affecting hearing and vision, is an autosomal recessive condition affecting 4 to 17 per 100,000 people and accounting for about 50 percent of hereditary deaf-blindness cases. Usher syndrome type II is caused by mutations of the USH2A gene, a 15.7 kb gene encoding the protein usherin, which localizes to photoreceptor cilium and cochlear hair cells. This subtype of Usher syndrome includes hearing loss from birth and progressive loss of vision, prompting retinitis pigmentosa (RP). Prime editing is a viable option for addressing USH2A mutations and restoring usherin expression and function. To begin, a HEK293T cell line needs to be established for subsequent testing of prime editors. Since prime editing to make the cell line was unsuccessful, homology-directed repair was done and successfully created a cell population with the mutation of interest (single base-pair deletion). Now that this cell population has been created, prime editors will be tested and optimized to address the mutation in a HEK293T cell line and potentially patient-derived induced pluripotent stem cells that are differentiated into photoreceptor precursor cells.