Gene therapies work through the delivery of a functional copy of a gene into cells. Adeno-associated viruses are a lucrative vector for this purpose, as they don’t stimulate an immune response and are replication-naive. This makes it possible to restore normal tissue function by restoring functional protein production.
Various mutations in different genes can cause heritable Ophthalmological disease. For example, loss of function mutations in the CHM gene leads to the progressive degeneration of the retinal pigment epithelium, photoreceptors, and choriocapillaris, a condition called choroideremia, while mutations in the RPE65 gene can cause Retinitis Pigmentosa 20, which leads to the degeneration of rods and cones, then, subsequently, the retinal pigment epithelium. Such diseases typically onset in childhood, however there is a therapeutic window when it is possible to administer a therapy and preserve vision.