The CRISPR-Cas9 genetic engineering technique is currently being tested on an adult patient with a rare form of blindness.
The patient has a rare hereditary eye disease known as Leber’s congenital amaurosis (LCA) which progressively leads to blindness, due to a gene mutation that blocks optical cells from manufacturing a protein which is vital for vision.
The US research team at the Oregon Health & Science University (OHSU) injected the treatment containing the CRISPR gene-editing directly in the patient’s eye behind the retina, under general anesthesia. This is where the photoreceptor cells are located, and where light is normally converted into nerve signals that the brain can understand. The hope is that when the diseased cells absorb the CRISPR gene-editing treatment, the patients’ DNA will repair itself in a way that restores their cells’ production of the missing visual pigments.
It may take up to a month to see whether the procedure restores the patient’s vision. If the outcome is successful, the scientists plan to enroll 18 additional patients in the study.
Eye surgery is not without risk, but there are also potential risks that CRISPR could make unintended mutations known as off-target effects. However the gene-editing tool stays in the eye and does not travel to other parts of the body.
This revolutionary line of research sparks hope and optimism and shows the high potential of this tool in the treatment of eye diseases.