01/29/2012 2 Comments Contact Our News Editors

The disease in humans and dogs is caused by defects in the RPGR gene and results in early, severe and progressive vision loss. It is one of the most common inherited forms of retinal degeneration in man.

"Every single abnormal feature that defines the disease in the dogs was corrected following treatment," said lead author William Beltran, assistant professor of ophthalmology at Penn's School of Veterinary Medicine.
"We were thrilled," said senior author Gustavo Aguirre, professor of medical genetics and ophthalmology at Penn Vet. "The treated cells were completely normal, and this effect resulted from introducing the normal version of the human gene into the diseased photoreceptor cells."

The similarities between humans and dogs, in terms of both eye anatomy, physiology, disease characteristics and positive response to this gene therapy, raise hope for a clear path to human therapies.

Beltran and Aguirre collaborated with Artur Cideciyan and Samuel Jacobson at the Scheie Eye Institute, part of the University of Pennsylvania's Perelman School of Medicine. This achievement results from more than 10 years of close collaboration between the scientists at Penn's veterinary and medical Schools and the University of Florida.

In addition to others at Penn Vet, Scheie and Florida, researchers at the universities of Michigan and Massachusetts and the National Eye Institute at the National Institutes of Health contributed to the research.

The study will be published in the journal Proceedings of the National Academy of Sciences.
The gene therapy approach used takes advantage of a viral vector — a genetically modified virus that doesn't cause disease and is unable to divide -- to deliver the therapeutic RPGR gene specifically to diseased rods and cones. In the absence of treatment, these cells malfunction and progressively die.