FRIDAY, March 23 (HealthDay News) -- Using experimental gene therapy in mice, University of Florida researchers turned off a gene that plays a major role in retinitis pigmentosa, a leading cause of inherited blindness.

This therapy involves injecting the eye with genetic material called interfering RNA, which disables the targeted gene, called rhodopsin, the researchers said. Normally, this gene is essential for healthy eyesight. But mutated versions of the gene can cause retinitis pigmentosa.

Mutated forms of rhodopsin produce a toxic protein in the retina that kills cells that receive light. Symptoms usually appear between the ages of 10 and 30, and most people are blind by age 40. Retinitis pigmentosa affects about 1.5 million people worldwide.

The UF team engineered the interfering RNA into a virus and injected it into the retinas of more than a dozen normal mice.

The treatment reduced the amount of rhodopsin by about 60 percent, the study said.

The findings, which are expected to be published in an upcoming issue of the journal Vision Research, suggest a possible method of treating people with retinitis pigmentosa.

"If we reduce the amount of protein formed by mutated rhodopsin, that may be sufficient to maintain vision in people who are affected by retinitis pigmentosa," Marina Gorbatyuk, assistant professor of molecular genetics and microbiology in the UF College of Medicine, said in a prepared statement.

The UF researchers now plan to study whether introducing normal rhodopsin to the retinas of mice will restore vision.

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