Glaucoma Gene Discovery May Spark New Treatments

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An investigative team from two universities has discovered a gene that is responsible for the most common type of glaucoma, an eye condition that affects an estimated 4 million Americans. This discovery could lead to new treatments for primary open angle glaucoma.

Glaucoma is a leading cause of blindness

Glaucoma is the second leading cause of blindness in the world and the main cause among African-Americans. Blindness associated with glaucoma accounts for 9 to 12 percent of all cases of blindness in the United States.

One of the strongest risk factors for primary open angle glaucoma (POAG) is elevated intraocular pressure; however, individuals typically do not know they have this risk factor because it is painless. Vision loss associated with open angle glaucoma begins with the side vision, which people may compensate for by turning their head, not noticing anything is significantly wrong until vision loss is more evident.

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Although scientists have known for many years that intraocular pressure rises in POAG because of a problem with the flow of aqueous humor out of the eye’s front chamber, the basic mechanisms behind the problem have not been understood. In the new study, researchers from Vanderbilt University and the University of Florida identified a gene responsible for open angle glaucoma, and the discovery came courtesy of beagles.

Decades ago, a colony of POAG-affected beagles was established to study treatments for glaucoma. Scientists in the new study used blood samples from the dogs and matched a specific spot on canine chromosome 20 with part of the human chromosome 19, an area associated with intraocular pressure.

Sequencing of the canine locus revealed a gene called ADAMTS10, which appears to be the strongest candidate associated with POAG. Beagles with primary open angle glaucoma have a single mutation in the gene.

Now researchers are trying to determine if the human ADAMTS10 gene is mutated in human cases of glaucoma. According to Rachel Kuchtey, MD, PhD, assistant professor of Ophthalmology and Visual Sciences and principal investigator, “if this gene truly plays a role in aqueous outflow regulation, we can begin to look at it—or its molecular patterns—as targets for treatments.”

SOURCES:
Glaucoma Research Foundation
Kuchtey J et al. PLoS Genetics 2011; 7(2): e1001306

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