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Can Gene Therapy Treat Leber Congenital Amaurosis?

Leber Congenital Amaurosis is a rare eye disease. It affects 1 in 80,000 people. This disease is hereditary, which means a baby gets this disease passed on to him from his parents. This disease damages theretina of eye in early childhood. There is a gradual deterioration in the working eye over the years leading to blindness. When the person is in his twenties, the effects become more obvious. Happily, recent advances made in the field of genetics can treat this rare disease. Read on to learn more.

 

What is Leber Congenital Amaurosis?

This disease targets the retina. It is present in the inner surface of eye. The image of different objects we see is formed on the retina, so it is like the film in a camera. When light hits the retina, a series of chemical reactions and electrical processes start. This forms a connection between the eye and the brain.  Then the brain provides meaning to what we see. The word Laber stands for the name of the scientist who discovered this disease. In the year 1869, a German ophthalmologist, Dr. Theodor Leber (1840-1917), first discovered this disease. Congenital refers to a condition which is present right from birth. Amaurosis means loss of vision but not because of damage caused to the eye by any disease or injury.

 

How is Leber Congenital Amaurosis Caused?

Genes are chemical instructions, which are followed by the organs to carry out the various functions of our body. According to Dr. Shalesh Kaushal, an eye surgeon at the University of Florida, a set of genes are identified which cause this disease. Among these genes, a particular gene named RPE65 plays a crucial role. This gene produces a protein which helps vitamin A in nourishing the retina. In patients suffering from Leber Congenital Amaurosis, the genes undergo a mutation, which is the technical name given to any change in the instructions of the genes. Because of the changes in the instructions, these genes do not produce enough Vitamin A for the retina. As a result, light is neither detected nor sensed in these patients causing blindness.

 

What Do Genetics have to Offer?

Genetics is a field of knowledge where everything associated with genes is understood and applied for human benefit. In the year 2001, researchers at the University of Pennsylvania and University of Florida successfully restored vision in experimental blind dogs using gene therapy. In this process, genes from another person’s body replace the genes of the affected person. When the gene RPE65 in these experimental dogs was replaced by gene therapy, vision lasted in them for 4 years. In 2007, it was decided that the experiments should be carried out on humans too. In 2008, 3 patients underwent gene therapy for treating Leber Congenital Amaurosis. According to the principal investigator, Dr. Samuel Jacobson from the University of Pennsylvania, vision was restored in these patients within a week. The results look very promising for carrying out further studies.

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