(Philadelphia, PA) -- Retinitis pigmentosa (RP) is an inherited eye disease that causes visual disability leading to blindness. Over the last 15 years, researchers have pinpointed defects in dozens of genes causing different forms of RP. Surprisingly, patients with the same genetic defect can show different severities of vision loss and rates of disease progression. This effect is most dramatic across the retina of some individuals where regions with normal vision can abut regions of no vision. Environmental factors have been near the top of the suspect list for this variation in severity. An environmental factor experienced by all, but to varying extents, is exposure to light bright lights have been previously speculated to accelerate certain forms of RP.
Now, investigators from the University of Pennsylvania and Cornell University provide evidence for retinal injury caused by moderate light exposure in dogs with a mutation in the rhodopsin gene. Since the blindness in these dogs mimics that observed in human RP caused by mutations in the rhodopsin gene, the investigators strongly recommend limiting excess light exposure in these patients.
"Rhodopsin is the light-catching molecule within rod photoreceptor cells that afford us with night vision," says Artur V. Cideciyan, PhD, Research Associate Professor of Ophthalmology at Penn's Scheie Eye Institute, and lead author of the current study published online this week in the Proceedings of the National Academy of Sciences.
"About 100 mutations in the rhodopsin gene have been shown to cause RP but our understanding of the steps between mutant proteins and death of rod photoreceptors remains incomplete," says Cideciyan. "What we know is that there are at least two ways in which rhodopsin mutations lead to blindness. Some mutations destroy vision in early life and children are left with only impaired day vision, which then disappears. In other mutations, night vision can be present throughout lifePage: 1 2 3 Related biology news :1
Contact: Olivia Fermano
University of Pennsylvania School of Medicine
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