For the first time ever, scientists have been successful in using gene therapy for improving vision in individuals with choroideraemia, a rare genetic cause of blindness. Choroideraemia results from a defect in the CHM gene causing progressive blindness in men.
Gene therapy offers a new hope in treating inherited diseases through genetic alteration or correction at the DNA level. A single successful treatment can often provide lifelong benefits.
Researchers treated 14 patients at the at Oxford University Hospitals NHS Foundation Trust using gene therapy. The procedure involved injecting a healthy copy of the CHM gene to affected retinal cells through a single injection given at the back of the eye.
Substantial vision improvement was seen overall in the treated patients by the end of the study. Of the 12 patients who did not have any treatment complications, 100% gained or maintained vision, which was sustained for up to 5 years compared with 25% vision maintenance in untreated eyes that were controls.
This successful trial was followed by a larger global gene therapy trial involving 100 participants across 9 countries in Europe and North America.