Duke Researchers Working to Isolate Glaucoma Gene in Ghana

RALEIGH, N.C.
In his waiting room, Dr. Rand Allingham saw all the evidence he needed of glaucoma’s disproportionate impact on his Black patients — the speed and intensity with which the disease ravaged eyes, robbing victims of their sight.

To find the reason, and a potential treatment, the ophthalmologist decided to seek an answer in the DNA of Blacks. His journey took him to Ghana, a West African nation where glaucoma is also widespread.
Allingham believes researchers have a better chance of finding the offending gene in Ghana because the nation is more than 98 percent African. He and his researchers hope the lack of outsiders in the population will help them isolate the gene or genes that lead to glaucoma in that nation — and possibly in Blacks in the United States, many of whom trace their ancestry to slaves brought to this country from Ghana.

Trying to find a potential genetic cause of glaucoma in Blacks is difficult in the United States, where Blacks have lived alongside Europeans, Asians and  American Indians for centuries, he says.

“I really didn’t think African-Americans came to this country and then developed glaucoma,’’ he says. “The U.S. is a melting pot. When you look at it genetically, 25 percent of African-Americans have European blood. Our population in the U.S. is not what you’d call a pure population genetically.’’

Glaucoma is the leading cause of irreversible blindness in the world and affects about 2 percent of the American population 40 years and older, according to the National Eye Institute in Bethesda, Md. Blacks are nearly three times more likely than Whites to suffer from the disease.
Glaucoma acts slowly. Over time, it prevents fluid from draining properly from the eye, increasing pressure and inflicting damage.

The disease rate isn’t known in Ghana, where no studies of glaucoma have been conducted, Allingham says. The entire country has about five ophthalmologists for its 18 million residents — and none specialize in glaucoma, says Pratap Challa, a researcher on Allingham’s team.
For the past eight years, Allingham and a team of researchers from Duke University have worked intermittently in Ghana, tending to glaucoma patients, teaching health care providers to treat eye disease and collecting blood samples from families with a history of glaucoma.
In Ghana, blindness often leads to a life spent in one room, alone, Allingham says.