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More than fifty-thousand american children are legally blind, and many of them were born with their visual impairment. Kids with Leber (lay-brr) Congenital Amaurosis (am-er-osis), or L-C-A, have one of the most common causes of hereditary blindness.
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Now University of Florida researchers have restored sight to chickens that are born blind because they have the same malfunctioning gene that causes L-C-A in children. Scientists delivered normal copies of the gene to developing embryos through a tiny hole in the egg shell. When the treated embryos hatched, the chicks were able to peck at small black dots that resembled seeds. They also were able to fix their gaze on moving visual patterns set up by the research team. meanwhile, untreated animals remained blind. Because chickens and people have a similar reliance on cone cells- the photoreceptors important for human vision- the blind chicken model provides a unique opportunity to study how this gene treatment might work in people.
Dr. Sue Semple-Rowland / UF neuroscientist
"As an animal model, since cone cells are most important to humans for vision, the chicken allows us to study the responses of those very important cells to disease, and then subsequently therapies to treat them."
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U-F researchers examined the retinas of the treated birds and found the treatment slowed but did not stop the course of retinal degeneration. Although the treated chickens could see, visual function was not permanently restored. The scientists are now working to improve the performance of the gene therapy with the goal of achieving long term restoration of sight in these animals.
Dr. Sue Semple-Rowland / UF neuroscientist
"I would estimate that within five years it would be possible to see the treatment for LCAǃ actually applied to human patients."
Voice-over:
At the University of Florida Health Science Center, I'm Mike Garrison
