Gene therapy in dogs can reverse retinal defects that lead to blindness in humans.

William Beltran and Gustavo Aguirre at the University of Pennsylvania in Philadelphia and their group targeted a form of retinitis pigmentosa. This is a common cause of blindness in which mutations in the gene RPGR lead to the death of light-sensing photoreceptors in the retina. The authors tested their gene-therapy approach in four dogs with mutations that model a form of the disorder. After injecting a virus carrying human RPGR into one eye of each animal, the authors found that the photoreceptors' structure appeared normal, and that their light-responsiveness had improved in three of the four treated eyes. In the untreated eyes, the cells were shrunken, fewer in number and less responsive to light.

The authors say that their findings open the door to gene therapy in humans for certain kinds of retinitis pigmentosa.

Proc. Natl Acad. Sci. USA http://dx.doi.org/10.1073/pnas.1118847109 (2012)