Finding Cause of Incurable Eye Disease
Study determines source of gene mutation that leads to retinitis pigmentosa
FRIDAY, Oct. 3, 2003 (HealthDayNews) -- The source of a gene mutation that causes retinitis pigmentosa has been identified by researchers at Dartmouth Medical School.
As well as providing a better understanding of the incurable eye disease, the study may also be a step forward in finding a way to treat retinitis pigmentosa (RP), which affects about 1.5 million people worldwide. Many people with the disease become legally blind by the time they reach the age of 40.
The Dartmouth scientists report their finding in the Oct. 3 issue of the Journal of Biological Chemistry.
They focused on the gene rhodopsin. It's a protein located in the back of the eye, one of several proteins that controls how the eyes detect light. Rhodopsin plays a role in the ability to see in dim or low-light conditions.
Retinitis pigmentosa, which affects the photoreceptors in the retina, begins with a single mutation within the rhodopsin protein. This mutation triggers a domino effect that, over a number of years, results in the death of retinal cells, destruction of the retina and eventual blindness.
"We wanted to concentrate on the reasons why rhodopsin is prone to misfold; that way we have the best chance of correcting that distortion before the disease can worsen," lead author Dr. John Hwa, an assistant professor of pharmacology and toxicology, says in a news release.
He and his colleagues pinpointed which of rhodopsin's 348 amino acids cause the mutation linked to retinitis pigementosa.
"We now have a molecular understanding of the abnormal proteins so we can move ahead to the ultimate goal of designing effective drugs to delay the degeneration that occurs to people suffering from RP," Hwa says.
He and his colleagues now plan to study the impact of certain vitamin A derivatives on the rhodopsin mutations.
Here's where you can learn more about retinitis pigmentosa.