Researchers find gene that causes some glaucoma
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ATLANTA (CNN) -- Glaucoma robs vision silently and painlessly. Pressure builds up on the optic nerve in the eye, eventually crushing it.
Sidney Mazer never suspected what was happening.
"I was just driving down the highway and my eyes were a little blurred," he says, "and I said, `Well, it's time to see about getting my glasses changed." In just a few weeks, he was virtually blind in his left eye.
While it may be too late for many, there is new hope for thousands of potential victims of the disease.
Researchers have discovered a gene that promises to let doctors detect glaucoma early enough to prevent thousands of people from going blind. The discovery is revealed by researchers in the latest issue of Science magazine due on the newsstand Friday.
The discovery is significant because it may prevent a vicious form of glaucoma, called open-angle glaucoma, that can be particularly destructive in children. It may also help in the early detection of a form of glaucoma responsible for approximately 100,000 cases of adult glaucoma each year.
Glaucoma is a plumbing problem
"This is a case where there's today a practical
application" for the discovery, says molecular geneticist Val Sheffield of the University of Iowa. Sheffield, one of the discoverers of the gene, says he expects to have a test for the gene within a year.
Glaucoma is essentially a plumbing problem. Fresh fluid builds up in the eye, but the old fluid doesn't drain out.
An estimated 3 million Americans have the disease. Because it causes no early symptoms, however, only half of those with the disease have been diagnosed and get medication or surgery to stall the disease's progress and save their remaining eyesight.
"It forms large aggregates, so it clogs things up," says another of the discoverers, Dr. Jon Polansky of the University of California-San Francisco. "The second thing it does is it binds a lot of materials that could be in that space, so it's a like a little plug."
Test will allow early treatment
The researchers have dubbed the protein with the acronym TIGR. Now that they've found the gene that produces TIGR,
doctors may soon be able to predict glaucoma, rather than just testing eyes for high pressure.
"I think this will give an early warning signal to people using this test and I think we are really on the verge of a breakthrough in that technique," says Polansky.
While not everyone with the defective gene will develop glaucoma, Sidney Mazer's doctor says he would want to know if he had the gene defect.
"And if I do, then I can be followed more carefully, checked much more frequently," says Dr. George Waring of the Emory Eye Center in Atlanta. "And if I don't, I may not have to
worry so much about whether or not I would get glaucoma in the future."
Even people who already have glaucoma may benefit someday from treatments aimed at blocking the TIGR protein... instead of just lowering eye pressure.
Says Polansky, "By getting at this protein, I believe
we are getting a handle on the cause of the disease and therefore can direct specific therapies toward that."
Correspondent Andrew Holtz contributed to this report.
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