What causes congenital blindness?

Genes in every cell provide a blueprint for your body, not only for physical characteristics like height, but functional ones, like sight.

An error in a gene is called a mutation. A mutation can send the wrong signal to the body or no signal at all.

Mutations in 265 different genes can cause forms of blinding disease. Many affect the retina, the bowl-shaped layer of light sensitive cells at the back of the eye.

One gene vital for sight is called RPE65. The gene delivers a derivative of vitamin A to the retina. Without this vitamin A derivative, the retina’s photoreceptors stop working. A mutation in RPE65 causes an inherited eye disease called Leber congenital amaurosis (LCA).

How does gene therapy work for Leber congenital amaurosis?

Gene therapy works by replacing a faulty gene with a healthy one, adding a new gene or knocking out a gene causing problems. Gene therapy can potentially be used to treat or prevent disease.

The gene therapy used at Penn to restore sight gives patients with LCA a normal copy of the gene RPE65. The patient receives a surgical injection in one eye and then, six to 18 days later, an injection in the second eye. The delay is to make sure the first eye is healing properly and allows the patient to have the patch removed before the second eye is treated. The treatment for both eyes typically takes two weeks.

The one-time treatment improved vision in the vast majority of patients, giving them greater independence to navigate tasks such as playing sports, using a computer and attending college.

To learn if this treatment is right for you or someone you love, please call 215-316-5132 or request a call-back online.

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