A Ray of Hope for Blind People - Gene Therapy

Terrific news for hundreds of thousands of people suffering from blindness! On Monday, US researchers announced that latest gene therapy trial, conducted on three young patients suffering from a rare form of blindness, proved successful after they reported better vision.

Researchers from University of Pennsylvania in Philadelphia, US, carried out the trail on three patients in their 20’s suffering from a genetic mutation, Leber congenital amaurosis or LCA, a severe inherited sight disorder. At present there is no specific treatment for the disorder.

The surgeons injected a virus - called an adeno-associated virus - containing a corrective gene into the eyes of the subjects and after 30 days the subjects reported ‘unprecedented improvement’ in their sights, Artur Cideciyan, ophthalmologist and co-author of the study and James Wilson of the University of Pennsylvania and the team reported.

The results, published this week in the Proceedings of the National Academy of Sciences, lend further support to identical results from other researchers all treating the severe inherited retinal degenerative disorder, LCA.

In 2007, a team of scientists from Britain carried out a similar procedure on three people with LCA and reported significant improvement in one of the patients earlier this year.

In gene therapy, doctors insert genesdefine into a person’s cells and tissues to treat a disease. The therapy aims to correct diseases by replacing malfunctioning genes.

Approximately 6 million Americans and more than 400,000 people in the United Kingdom suffer from age-related macular degeneration (AMD), the main cause for loss of central vision, and the technique could be tested on these patients within three years, researchers said.

They also added that the technique could be ready for use within 24 months to treat some other inherited diseases of the retina, which affect 20,000 Britons.

LCA is the most common inherited cause of blindness in childhood. It is characterized by a severe retinal dystrophy before the age of twelve months and total blindness by the time a person reaches adulthood. It affects nearly one in 80,000 people in the UK and is responsible for one in 10 severe sight disorders in children.

Since the disorder is caused by a mutation in a gene called RPE65, the researchers used the healthy copies of RPE65 genes into the eyes of patients to correct the disorder.

Artur Cideciyan said, "We checked whether it was day or night vision or both that was restored by this therapy. We found that both are corrected or restored in this condition." He further added, “The patients are saying, 'There is a difference in my vision - things are looking brighter. The colors are more vivid and I am seeing colors'."

The scientists said that there was a fifty fold improvement in cone function, responsible for color and day vision and an astonishing 63,000 fold improvement in rod function, which controls night vision.

However, the sight in the treated eyes was not 100% perfect as the subjects were showing an abnormally slow adaptation to ‘low light levels’. The study was funded by the National Eye Institute (NEI), part of the America’s National Institutes of Health (NIH).