LCA is a rare genetic eye condition that develops at birth or in infancy and is usually noticed due to a lack of visual responses and nystagmus (wobbling of the eyes).
It was first described by Theodore Leber a German Ophthalmologist in 1869. It accounts for at least 5% of all retinal dystrophies and 20% of children attending schools for the visually impaired.
Symptoms include nystagmus (involuntary jerky rhythmic eye movement), photophobia (sensitivity to light) and slow pupillary response to light.
LCA may be isolated to the eyes or arise as part of a syndrome. For instance Senior-Loken syndrome comprises LCA with kidney disease and Joubert syndrome comprises LCA with developmental delay, and cerebellar problems (part of the brain that controls coordination and movement).
LCA usually has an autosomal recessive inheritance pattern. Scientists have identified 24 genes that when mutated can each cause LCA. These genes account for about 75 percent of all cases of LCA.
One of these genes, called RPE65, causes a relatively mild form of LCA, and three clinical trials (one in the UK and two in the USA have been undertaken to assess the safety and effectiveness of a treatment for this form of LCA, by injecting a replacement RPE65 gene into the retina of people who have been identified as having LCA due to a defective RPE65 gene. These trials have shown this approach to have acceptable safety and all studies showed evidence of improvements in retinal sensitivity and visual function.
The results of these three trials are very encouraging, and support the continued efforts to optimise and develop gene therapy approaches for inherited retinal diseases.