WEDNESDAY, Aug. 25 (HealthDay News) -- Researchers have
identified a gene linked to an inheritable eye disease that affects
5 percent of U.S. residents over 40 and is the most common cause
for transplants of the cornea.
The genetic disorder, known as Fuchs corneal dystrophy (FCD),
causes tiny bumps on the cornea -- the thin, clear membrane that
covers the front of the eye -- that can lead to blurred vision, eye
pain and swelling and, in advanced cases, to a marked loss of
"The association we found is novel and identifies the first gene that is a major contributor to FCD," said study senior author and research team leader Dr. Albert Edwards of the University of Oregon in Eugene, whose report appears in the Aug. 25 online version of the New England Journal of Medicine.
Previous work has identified three genes that are associated
with rare subtypes of Fuchs, but the genetic basis of the most
common form of the disease was not understood.
The authors analyzed the genomes of 280 people with Fuchs and
410 people without the disease. They found that people with
particular versions of a gene called transcription factor 4 (TCF4)
were much more likely to develop FCD.
People with one copy of a high-risk version of TCF4 were five
times more likely to develop FCD as were people without one of
these versions; those with two copies were 30 times as likely to
develop the disease.
The researchers are not sure through what mechanism altered
forms of TCF4 might cause FCD, although they suspect that it may
involve a protein called E2-2. TCF4 encodes E2-2, which is involved
in cellular growth and differentiation and is expressed in the
Only a small percentage of patients with FCD require a corneal
transplant, according to the researchers, but in advanced cases
causing major vision loss, it is the standard treatment.
The researchers have identified a "robust association" between
TCF4 and the development of Fuchs, but they have not yet shown a
causal relationship, said Dr. John Gottsch, a professor of
ophthalmology at the Wilmer Eye Institute at Johns Hopkins
University, who in other studies has identified chromosomes linked
to rare FCD subtypes. It's not clear how different versions of TCF4
might lead to the development of the disease, he said.
According to Edwards, understanding the genetic predisposition
for FCD may be helpful for selecting participants for future
studies on the condition, especially for research aimed at
understanding if this genetic risk predicts its progression.
Developing a genetic test for FCD could also help surgeons avoid
transplanting donor corneas that might eventually develop the
disease, he said.
"The real impact of what we've done is to determine the biological underpinnings of the disease," Edwards said in a university news release. "We've identified a protein that is probably involved, and that will allow us to, hopefully, identify a method to prevent people from losing their vision."
Find out more about Fuchs corneal dystrophy at the
U.S. National Eye Institute.
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