If ongoing studies in dogs go well, the researchers said, the first human studies could begin in the next three to four years. But that said, it's hard not to get very excited about this, because it's a very dramatic result. I mean, basically these dogs were blind and now they are not blind anymore. Children with LCA have little or no vision at birth, and what little may be there is lost over time. It occurs when there is a defect in any of several genes that help convert light into electrical signals in the eye.
Parents carrying the defect on one copy of the gene have normal vision.
Mutations in any of a dozen or so other genes also cause LCA, and mutations in scores of others cause other forms of retinitis pigmentosa. Jean Bennett, Maguire's wife and co-worker at the Scheie Institute's F.M. Kirby Center for Molecular Ophthalmology, led the study, in which thousands of viruses were injected directly into the eyes of three blind Briards. The viruses had been genetically engineered by scientists at the University of Florida to contain healthy versions of the RPE65 gene, which the viruses then delivered to the dogs' ailing retinal cells. But the right eyes received injections directly behind the retina, very close to the retinal pigment epithelial cells where the RPE65 gene does its job. Before long, all three dogs had vision in their right eyes.