An international research team has discovered a gene that, when mutated, causes one of the most common forms of inherited blindness in babies. Scientists at the University of Leeds, working in collaboration with experts from other centres around the world, identified the gene, which is essential to photoreceptors in the eye, the cells that "see" light.
The finding, the thirteenth gene to be linked to Leber’s congenital amaurosis (LCA), comes at a time of hope for the people born with the disorder. Scientists at Moorfields Eye Hospital, London, recently announced the start of clinical trials for a gene therapy involving injecting genes into the eye of patients with LCA to restore their sight. The finding of the new LCA gene, based on work funded by the Wellcome Trust and local charity Yorkshire Eye Research, appears in this month's edition of the journal Nature Genetics.
The newly-discovered gene, LCA5, is involved in the production of lebercilin, an essential component of photoreceptors in the retina. Lebercilin is found in other tissues as part of the cilia, finger-like projections from the surface of cells capable of moving molecules around. However, mutations in the LCA5 gene only appear to cause defects in the retina.
"We already know of a dozen genes which, when mutated, cause LCA," says Professor Chris Inglehearn from the Leeds Institute of Molecular Medicine at St James's Hospital, Leeds. "This new gene is the thirteenth and adds a substantial new piece to a growing body of evidence that defects of the cilia are a major cause of inherited blindness. In that sense, we can consider this a 'lucky thirteenth' as we are building a much clearer picture of what causes the disorder."
Professor Inglehearn believes that lebercilin may be involved in moving proteins from the inner to outer segments of photoreceptors in the retina. Protein transport is essential within retinal photoreceptor cells as they are long, thin cells with