Gene editing tool used inside body for first time, to treat rare form of blindness

Scientists say they have used the gene editing tool CRISPR-Cas9 inside a person’s body for the first time, a new development in efforts to operate on DNA to treat diseases.

A patient recently underwent a procedure at the Casey Eye Institute at Oregon Health & Science University in Portland for an inherited form of blindness. 

It may take up to a month to see whether the procedure worked to restore vision. If the first few attempts seem safe, doctors plan to test the technique on 18 children and adults.

Dr Jason Comander, an eye surgeon at Massachusetts Eye and Ear in Boston, another hospital that plans to enrol patients in the study, said it marked “a new era in medicine” using a technology that “makes editing DNA much easier and much more effective”.

Doctors first tried in-the-body gene editing in 2017 for a different inherited disease using a tool known as zinc fingers. Many scientists believe Crispr is a much better tool for locating and cutting DNA at a specific spot, and interest in the new research is very high.

The technique was used to treat Leber congenital amaurosis, caused by a gene mutation that keeps the body from making a protein needed to convert light into signals to the brain, which enables sight. Patients with this condition are often born with little vision and can lose even that within a few years.

The Macular Society is currently funding a research project investigating CRISPR-Cas9 gene editing as a therapy for a form of Bestrophinopathies. The aim of the project is to test whether the gene editing tool can be used as a treatment for Autosomal Dominant Bestrophinopathies. In an autosomal dominant condition a faulty gene from one parent overrides the healthy gene from the other parent. The faulty gene creates a toxic protein which damages the cells of the retinal pigment epithelium (RPE) leading to sight loss. In this project at University College London's Institute of Ophthalmology, researchers aim to cure dominant bestrophinopathies by using gene editing to cut out the faulty gene and leave the healthy one untouched. They will test whether it is working as planned using patients' skin cells, as well as stem cells and RPE cells created from patient skin cells.