Einstein Researcher Heads Pioneering South Pacific Blindness Study

By on 04/11/2017

1024px-ChuukA small island in the Pacific—8,000 miles from Philadelphia—may help an Einstein Healthcare Network physician unlock a medical mystery.

Weno is one of 11 islands that make up Chuuk, which is one of the Federated States of Micronesia. It’s about 600 miles southeast of Guam, and 3,370 miles southwest of Hawaii. Chuuk has a population of around 55,000. About 16,000 reside on Weno, the state’s capital. A direct flight from Philadelphia to Chuuk International Airport, if you could get one, would take nearly 17 hours.

If this sounds like a travelogue, it’s not. In many ways, Chuuk is a tropical paradise. Many of the islands have broad beaches. There are swaying palm trees, vast swaths of jungle, mangrove swamps and coconut plantations, and the ocean surrounding the islands is well known for its World War II wreck diving.

Against this backdrop of natural beauty, however, there exists the unsettling reality of grinding poverty. Per capita income stands in the range of $2,500 to $3,000. More than 17 percent of islanders survive on an average of $1.90 a day. Most people support themselves through subsistence farming or fishing. Many are malnourished.

Chuuk is also known for its abnormally high rate of two devastating eye disorders, anophthalmia and microphthalmia (A/M). Both can cause blindness.  A/M are on the same spectrum of disorders, with anophthalmia being the most severe form.   In the general population, A/M occurs at a rate of three per 10,000 births. In Chuuk, the incidence is 14 per 10,000 births. A child born with anophthalmia is missing one or both eyes. In microphthalmia, one or both eyes are abnormally small and deformed.

Why are so many Chuukese babies born with A/M? What can we learn about A/M from this remote island population? Most of all, aside from what we can learn, is there anything that can be done to reduce or prevent A/M from occurring, to reduce the suffering of an already burdened island population?

More than 17 percent of islanders survive on an average of $1.90 a day. Most people support themselves through subsistence farming or fishing. Many are malnourished.

In mid-April, Adele Schneider, MD, director of Clinical Genetics at Einstein Medical Center Philadelphia, headed up a team of genetic researchers and vision experts to Weno to learn what they can about the genetic underpinnings of A/M, to try to determine whether certain environmental factors might contribute to the problems, and to provide badly needed ophthalmological services.

The Genetics Department at Einstein is internationally renowned for its Anophthalmia/Microphthalmia Clinical Research Center, which includes a registry and gene screening. The program was initiated with an Albert Einstein Society grant, and has been sustained by the Society, together with other grants, over the years.

Whatever happens at the genetic level occurs either at the time of conception or very early in pregnancy, says Dr. Schneider. “It’s there at the time of birth, and is caused by something that happened early in pregnancy because the eye develops up to 56 days of gestation,” Dr. Schneider says. “By then, whatever genes are influencing the development of the eye have done their job.”

Earlier in the study of anophthalmia/microphthalmia, researchers considered that there may be an environmental cause—exposure to pesticides, for example. However, research has for quite some time pointed to a genetic cause.

Dr. Schneider’s primary motivation is to provide aid to people who could really use it, but at the same time Chuuk provides an ideal opportunity to get at the genetic roots of A/M.

“We want to find out the genetics of anophthalmia/microphthalmia in these children,” she says. “I think it’s probably going to be one gene and probably the same mutation in everybody because it’s an island population that’s intermarried, so they’re all related in some way, even distantly. And it appears that the A/M seems to have hit this generation with a large number and wasn’t present before in such large numbers, so I’m not quite sure why. So that’s another curious thing.”

Dr. Schneider is hopeful that, regardless of the role nature plays in the development of these disorders, there might be a way to prevent them. One theory: prenatal vitamin A insufficiency.

“There’s endemic vitamin A deficiency there (in Chuuk),” she says. “Vitamin A levels can affect the function of some genes in the vitamin A pathway and involved in eye development.  Some of these genes have been shown to be dependent on the mother’s vitamin A level for normal functioning. So wouldn’t it be amazing if we found that low vitamin A is affecting the function of a gene and causing it, and if we gave them a high enough dose of vitamin A, we could prevent it?”

Aside from the obvious physical hardship of blindness caused by anophthalmia and microphthalmia, there are other compelling reasons to explore and address A/M in Chuuk. “This is a big economic and educational burden for them,” says Dr. Schneider. “So, it would be nice if we could figure out a way of preventing it in the next generation—and also, if the people who have it get examined by an ophthalmologist. Many of them have never had an eye exam. And one of the problems is that glaucoma can make your vision worse. So, if there are younger kids who are at risk for glaucoma and can get examined now, we may be able to prevent the development of glaucoma in these children and provide guidance as to how to manage it. So, there are a lot of reasons to go there.”

(Adele Schneider photo by Wes Hilton)



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