Gene Therapy May Help Restore Sight in People With Eye Disease

A new type of gene therapy has been found to reverse some vision loss in people with certain degenerative eye diseases. The goal is to start treatment as early as possible in order to save as many light-sensing cells as possible. There is a window of time that gene therapy needs to be applied before vision damage is beyond repair. The earlier treatment is applied, the better the prognosis.

The surgical procedure used is risky since it involves detaching delicate retina tissue, but no complications have been reported. In fact, most participants report the ability to detect more light, read more letters and numbers, and see the stars at night. All of these things are major improvements for people who are used to very little vision, like Jonathan Wyatt in this article who was one of six people to receive treatment for choroideremia.

Choroideremia is the main condition studied in this work. It is an eye disease linked to a gene on the X chromosome. It is a rare disease that affects an estimated one in 50,00 people. Because it is X-linked, it primarily affects males. The disease usually begins in childhood and causes the progressive narrowing of vision and loss of the rods and cones and usually ends in blindness.

The treatment adds a working copy of the associated gene to the retinal cells of patients with the disease. This can be done by lifting the retina and injecting the gene therapy into the space created.

Other groups are working on developing gene therapies for retinal diseases as well. It is too soon to know for sure if this treatment will be appropriate for use in more patients and if it can stop the loss of retina tissue. It may take a few years, but researchers are hopeful.

Though this was a small trial and there is still a lot to learn from the experimental trials, this could be promising for patients with choroideremia. If it is successful, similar therapies could be applied for other genetic eye diseases for which there is not current treatment or cure. Hopefully more research will be done so that we can learn more about gene therapy use in eye disease.

Article: http://www.technologyreview.com/news/519426/gene-therapy-tested-as-a-way-to-stop-blindness/

Possible treatment for X-linked pigmentosa

An article in Science Daily states that gene therapy will soon be used to treat a condition called X-linked retinitis pigmentosa. This genetic defect affects young children who are born with full vision, and by the time they are about 20 years old, they are completely blind. The researchers in the University of Florida have found a way to replace the light-sensitive cells in the eye with genetically altered light receptor cells. “The UF researchers and colleagues at the University of Pennsylvania performed the technically challenging task of cloning a working copy of the affected gene into a virus that served as a delivery vehicle to transport it to the appropriate part of the eye. They also cloned a genetic "switch" that would turn on the gene once it was in place, so it could start producing a protein needed for the damaged eye cells to function.” Researchers are nearing the end of trials in animals and soon hope to begin human testing, with the hopes of curing blindness in the near future.