‘Miracle’ Gene Therapy To Cure Blindness Also Strengthens The Brain

By: Charles Q. Choi
Published: 07/20/2015 07:11 AM EDT on LiveScience

Treating people who are blind with gene therapy can not only restore their vision, it can also strengthen visual pathways in the brain, even in people who have been nearly blind for decades, researchers say.

Since 2007, clinical trials using gene therapy have often dramatically restored people’s sight. Dozens of children and adults who were blind or near blind have become partially sighted, gaining the ability to navigate almost normally visually.

“Seeing how their visual function has improved and how it affects their daily lives has been extraordinarily gratifying,” study co-author Dr. Jean Bennett, a gene therapist at the University of Pennsylvania in Philadelphia, told Live Science.

The basic strategy for these clinical trials is to inject a harmless virus that inserts good copies of genes that are defective in the individual. These genes are inserted into cells in the retina, the tissue that lines the inner eyeball and senses light.

“The results are amazing — a miracle,” study lead author Manzar Ashtari, a neuroscientist at the University of Pennsylvania in Philadelphia, told Live Science. [5 Crazy Technologies That Are Revolutionizing Biotech]

But a question dogging these clinical trials is how well the brain’s visual pathways can recover even if a person’s retinal function has improved. The visual pathways are bundles of nerve fibers that connect the retina in the eye to the visual cortex in the brain, where visual information is processed. After years of near-total blindness, unused pathways inevitably weaken and shrink.

The new findings show that restoring a person’s sight with gene therapy also helps strengthen the visual pathways of the brain.

The researchers looked at 10 patients with a rare inherited disease called Leber’s congenital amaurosis Type 2 (LCA2), which causes the retinas to degenerate slowly. People with this disease —> Read More