Gene Therapy Prevents Blindness in Mice

Condition leads to vision loss in 1 of every 5,000 boys, researchers say

WEDNESDAY, Aug. 10, 2005 (HealthDay News) -- Researchers at the University of Florida's Genetics Institute successfully used gene therapy in mice to treat retinoschisis, a rare incurable genetic eye disease that affects boys.

The findings, published in the August issue of the journal Molecular Therapy, suggest this gene transfer method may eventually be used to treat retinoschisis and other eye diseases in humans caused by single gene defects.

Currently, there is no treatment for retinoschisis. The disease, which is first detected between the ages of 5 and 10, leads to blindness in about one of every 5,000 boys.

"These children lose their sight gradually, often with devastating results. What happens is the retina actually begins to split in the middle, causing loss of central vision -- that's the vision that you need to be able to read or walk around," William Hauswirth, professor of ophthalmic molecular genetics, said in a prepared statement.

In a healthy eye, retinal cells secrete a protein called retinoschisin (RS1), which acts like a glue to bind the layers of the retina. Boys with retinoschisis lack the ability to secrete RS1. The absence of this protein causes the retinal layers to separate and leads to the formation of tiny cysts.

In this study, the researchers injected a healthy version of the human RS1 gene into the sub-retinal space of the right eyes of mice that lacked the healthy gene needed to maintain the retina. The left eyes of the mice were left untreated. After six months, the treated right eyes appeared healthy while the untreated eyes showed clear signs of disease damage, the researchers said.

More information

The Foundation Fighting Blindness has more about retinoschisis.

SOURCE: University of Florida, news release, Aug. 8, 2005
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