Researchers at the University of Pennsylvania School of Medicine and the Center for Cellular and Molecular Therapeutics at The Children’s Hospital of Philadelphia used gene therapy to treat five children (age range: 8 to 17)and seven adults (maximum age of 44 years) born with Leber’s congenital amaurosis (LCA). All of the patients treated showed marked improvement in vision but the best improvements were seen among the children who, after the treatment were able to navigate a low-light obstacle course. Six of those treated are no longer classified as legally blind.
One of the patients, a 9-year old boy showed a “spectacular” recovery of vision after just 1 dose of gene therapy that allows him to play sports like other children.
Leber’s congenital amaurosis (LCA) is a group of inherited blinding diseases that damages light receptors in the retina. It usually begins stealing sight in early childhood and causes total blindness during a patient’s twenties or thirties. Currently, there is no treatment for LCA. LCA affects around 1 in 80,000 population.
About the therapy:
The therapy entails a single injection of genes that produce proteins to make light receptors in the retina. The researchers sued a vector to carry the genes. The research team used a vector, a genetically engineered adeno-associated virus, to carry a normal version of the gene, called RPE65, that is mutated in one form of LCA, called LCA2, that accounts for 8 to 16 percent of all LCA cases.
Effectiveness of the therapy was best seem among the children treated. Since LCA is a progressive disease which damages the retina, treatment is best when progression is stopped or delayed at a very early stage when retinal damage is still minimal.
According to principal author Dr. Albert M. Maguire
Gene therapy is relatively new development and is still in the experimental stage. The patients in the current study were among the first to receive gene therapy for a non-lethal disease. The children were the youngest so far to be treated with the therapy. The patients will be closely monitored in the coming years for signs of side effects or regression.
This new therapy gives hope to people with vision problems, not only those with LCA but other forms of retinal degeneration.