Gene Therapy

Gene therapy is an experimental technique that uses genes to treat or prevent disease. Currently, there are a lot of studies and experiments that allow doctors to treat a disorder by inserting a gene into a patient’s cells instead of using drugs or direct surgery. Researchers are testing several approaches to gene therapy, such as replacing a mutated gene that causes disease with a healthy copy of the gene, inactivating, or “knocking out,” a mutated gene that is functioning improperly, introducing a new gene into the body to help fight a disease, and helping to regenerate precious cells. Although gene therapy has a very active and promising approach for a number of disease, there are still several risks and side effects. Hence, the therapy

is currently only being tested for the treatment of diseases that have no other cure. One of the major field of studies related to gene therapy is how fighting with degenerating retinal cells related to blindness.

When the human eye is watching a sunset, an intricate series of events take place.

Light passes through the cornea, and is refracted and focused on the retina. The retina is a thin, delicate tissue located at the back of the eyes that contains photoreceptor cells that detect light and convert it into electrical signals that are sent to the brain. The photoreceptor cell relies on a protein encoded by gene RPE65 for the production of a type of vitamin A that allows light sensitive photoreceptor cells to function. The RPE65 protein is produced in a thin layer of cells at the back of the eye named retinal pigment epithelium. About 10% of people with Leber congenital amaurosis (LCA), an inherited disorder that causes vision loss starting in childhood, have an altered form of the gene RPE65. The researchers hoped to halt this process by using a virus to shuttle a functional RPE65 gene into the retina. This strategy, in which genes are used to treat or prevent a disease is known as gene therapy. Clinical trials of experimental gene therapy for LCA and other diseases that affect the retina has been progressing in the past decade. In 2007, researchers at the University of Pennsylvania and the University of Florida pinpointed an area of intact photoreceptors in the retina of 3 patients aged 22, 24, and 25. They then injected healthy copies of the RPE65 gene under the retina in this area. The phase one of clinical trial is also supported by the NIH’s National Eye Institute

(NEI).