Gene therapy provides lasting improvement to sight

Researchers in the US have found that gene therapy can lend lasting benefits to individuals with a rare inherited eye disease, Leber Congenital Amaurosis (LCA), which causes retinal blindness in children.

A study published in the journals Human Gene Therapy and the New England Journal of Medicine (NEJM) details the cases of three individuals with LCA who all exhibit greatly improved vision one year on from their original gene therapy treatment.

The patients were all in their early or mid 20s and received gene therapy targeting their mutated version of the RPE65 gene. This gene is crucial to the proper functioning of the retina and the mutation responsible for LCA results in the retina losing its photosensitivity.

Even one year after a healthy version of RPE65 gene was injected under the retina, the gene continues to produce the RPE65 protein, thus increasing the retina's light sensitivity.

One patient was even able to read an illuminated clock, something they found impossible even directly after the gene therapy. According to the study's authors, this indicates that the brain is able to adapt to the newly improved vision.

The study was led by Artur V. Cideciyan, PhD, research associate professor of ophthalmology at the University of Pennsylvania School of Medicine along with colleagues at the University of Florida, Gainesville.

"This fascinating finding shows that a person can adapt to the new vision resulting from gene therapy over a prolonged period of time," said Samuel G. Jacobson, professor of ophthalmology at Penn Medicine's Scheie Eye Institute and principal investigator of the clinical trial. "We will look closely at whether these slow visual gains could be accelerated with visual training in future studies."