Researchers at University College London are the first in the world to attempt to use gene therapy to treat a rare inherited conditionwhich leads to blindness in childhood. The disease, known as Leber Congenital Syndrome (LCS), is caused by an abnormality in the RPE65 gene, which stops the retina from being able to sense light properly. At best, people with the disease are able to detect light and dark or close range hand motions only.
Twelve young adults affected by the disease have volunteered to take part in pioneering trials at Moorfield's Eye Hospital in London, in the hope that some of their vision could be restored.
Each volunteer has undergone a complex operation, during which working copies of the defective gene are injected into the retina at the back of the eye. Here a harmless virus delivers the good copy of the gene into the cells.
'Some indications of the results of the trial may be available within several months', says leading retinal specialist Professor Tony Moore, who has been involved in conducting the trial. 'However, the subjects will need to be followed-up to assess the long term effect of the treatment. It will be many months before we have the full picture', he added.
Speaking to the BBC, one volunteer confessed he had mixed feelings about taking part: 'It's very difficult to say how I'm feeling', he said. 'I keep ranging from extreme nervousness to a bit of excitement'.
The researchers have already successfully tested the treatment in dogs suffering from LCS, whose vision was successfully restored to the extent that they could walk through a maze without difficulty. However this is the first time the treatment has been tested in humans.
Professor Robin Ali, who is leading the research, says 'We have been developing gene therapy for eye disease for almost 15 years but until now we have been evaluating the technology only in the laboratory. Testing it for the first time in patients is very important and exciting and represents a huge step towards establishing gene therapy for the treatment of many different eye conditions'.
Speaking to Reuters, Professor Andrew George, a leading immunologist at Imperial College in London, anticipates that these trials may only be the tip of the iceberg: 'The eye is good for gene therapy because it is easy to see what's going on', he says. 'There is hope that once gene therapy is developed in the eye, scientists could move on to more complex organs'.
Sources and References
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First trial of gene therapy to restore human sight
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Gene therapy first for poor sight
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Doctors test gene therapy to treat blindness
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