Mutant gene could be sight for sore eyes

12 February 2010

The discovery of a mutant gene linked to a type of inherited blindness could help to save the sight of some patients by enabling doctors to catch the disorder early.

An international research team, part-funded by the Wellcome Trust, found that some patients with a disease known as FEVR - Familial Exudative Vitreoretinopathy - have a faulty version of the gene TSPAN12, which affects the development of the eye.

While many FEVR patients are registered blind or visually impaired, members of the same family may carry the faulty gene without showing any symptoms. By screening these family members for TSPAN12 mutations, doctors may be able to catch FEVR early on and treat patients before they start to lose their sight.

Dr Carmel Toomes from the Leeds Institute of Molecular Medicine, who led the research, said: "This discovery will have an immediate impact on the treatment and counselling of some FEVR patients by allowing us to identify family members who carry the mutated gene before any retinal damage has occurred. This decreases their chances of going blind because if a patient is diagnosed early enough their sight can often be saved by surgical intervention."

TSPAN12 is thought to cause FEVR by disrupting the cell signals required for the normal development of blood vessels in the retina at the back of the eye.

This study looked at 70 FEVR patients who had tested negative for the three genes already known to cause the disease. Mutations in the TSPAN12 gene, which is located on chromosome 7, were found in 10 per cent of these patients.

As well as being an important piece in the FEVR puzzle, this latest discovery will help scientists to understand other blinding disorders including age-related macular degeneration and diabetic retinopathy - two of the leading causes of blindness in the developed world.

"Our research highlights how studying rare inherited disorders such as FEVR can help us identify the genes and pathways involved in the basic cellular processes which underlie more common diseases," added Dr Toomes.

"We hope that by learning more about blood vessel formation process in FEVR we will gain clues that may lead to new treatments for these conditions in the future."

The research will be published in the 'American Journal of Human Genetics' on 12 February.

Image: Composite image of the left eye incorporating multiple retinal scans. Credit: Shelley James, Wellcome Images

Reference

Poulter JA et al. Mutations in TSPAN12 cause autosomal-dominant familial exudative vitreoretinopathy. Am J Hum Genet 2010;86:248-253.