GAINESVILLE, Fla. -- University of Florida researchers used gene therapy to restore sight in mice with a form of hereditary blindness, a finding that has bearing on many of the most common blinding diseases.

Writing online in todays (May 21) edition of Nature Medicine, scientists describe how they used a harmless virus to deliver corrective genes to mice with a genetic impairment that robs them of vision.

The discovery shows that it is possible to target and rescue cone cells the most important cells for visual sharpness and color vision in people.

"Cone vision defines whether someone is blind or not," said William W. Hauswirth, Ph.D., the Rybaczki-Bullard professor of ophthalmic molecular genetics in the College of Medicine and a member of the UF Genetics Institute. "If you can usefully deliver a gene specifically to cone cells, there are implications for all blinding diseases, not just inherited ones. Even in two very common types of blindness, age-related macular degeneration and diabetic retinopathy, if you can target cones you might be able to rescue that vision."

Scientists experimented with mice with a form of hereditary blindness called achromatopsia, which affects about 1 in 30,000 Americans by disabling cone photoreceptors in the retina. The disease results in nearly complete color blindness and extremely poor central vision.

Within two months of the gene therapy injection into the subretinal space of the mouse eyes, scientists measured the electrical activity in the retinas, finding that 19 of the 21 treated eyes positively responded to therapy, and 17 of those 19 had electrical readings from their retinas on par with those taken in normal mice.

When the mice were between 6 and 7 months old, tests showed 18 of the 21 treated eyes continued to respond normally.

In addition, a separate, smaller group of treated mice were evaluated using an exam akin to an eye test at the doctors offi
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Contact: John D. Pastor
jdpastor@ufl.edu
352-273-5815
University of Florida
21-May-2007