An international team of scientists from New Zealand, Australia and the UK — including Prof. Colin Willoughby from the University of Liverpool — has identified a specific gene that plays a key role in epithelial recurrent erosion dystrophy (ERED), a genetic corneal dystrophy disorder that causes abnormality of the outer layer of the eye. The discovery solves a 20-year-old puzzle for a family in Liverpool, UK, who all developed ERED.
Normal anatomy of the human eye and orbit, anterior view. Image credit: Patrick J. Lynch / CC BY 2.5.
The Liverpool family, Ridland and Kadiri, first met Prof. Willoughby in 1996. They had a type of corneal dystrophy, as yet unidentified, which caused spontaneous, recurrent, painful scratches on the cornea from early life.
In discussion with his colleague, Dr. Andrea Vincent from the University of Auckland, Prof. Willoughby learnt that there were similar families in New Zealand and Australia.
Working together they sought to characterize the gene responsible for this particular disorder by using genomics.
“Technological advances in the clinic and laboratory have allowed us a greater appreciation of the observable physical or biochemical characteristics of an organism and the genetic diversity of corneal dystrophies,” Prof. Willoughby said.
“As a result of this study we are now able to offer a genetic diagnosis of the disease before the actual symptoms of the disease have appeared.”
“We can also give advice to parents concerning the risks associated with this disorder in a child.”
According to the team, ERED is a rare form of superficial corneal dystrophy which affects the clear window on the front of the eye.
Patients develop recurrent, painful scratches on the cornea damaging its outermost layer and healing with a scar. These erosions which usually commence in childhood are painful and lead to intense light sensitivity and reduced vision.
Laser treatment can help alleviate the symptoms and although this does not cure the disease it does slow it down.
No treatments are available to correct the genetic defect at the present time.
“The protein identified in this study is called collagen 17 (COL17A1) and it has a pivotal role in the skin. And, from this study, the eye,” explained Dr. Kevin Hamill from the University of Liverpool.
“Understanding the function of these types of proteins has broader implications for wound healing in the body and scarring in the eye.”
The results were published in the April 2016 issue of the journal Ophthalmology.
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Verity F. Oliver et al. 2016. A COL17A1 Splice-Altering Mutation Is Prevalent in Inherited Recurrent Corneal Erosions. Ophthalmology, vol. 123, no. 4, pp. 709-722; doi: 10.1016/j.ophtha.2015.12.008
