Gene Therapy to Treat Macular Degeneration

In Boston, scientists are working at the frontier of genetic research in an attempt to cure Macular Degeneration, the leading cause of blindness in the U.S., an enormous task.

Rajendra Kumar-Singh: There are about 3 billion nucleotides in the human genome and just 1 small mistake is sufficient to cause a problem. And when that problem occurs it can lead to inherited retinal degeneration.

Dean Bok: The promises of gene therapy at this point in time are tremendous. In principal, one can replace a bad gene with a good one. It’s easier to replace a gene that’s recessive, where you need two bad ones in order to produce the disease, and that’s where we’ve had success. The challenge is for genes that are dominant. You need to get rid of the bad guys before the good guys can do their work.

Rajendra Kumar-Singh: Because the source of inherited retinal degeneration is DNA, it makes sense to be able to deliver normal DNA to correct the defect and hence gene therapy is going to be a key player in trying to develop novel therapies for these inherited retinal degeneration.

Narrator: (Animation) An imbalance in the complement system, which helps to fight many diseases, can cause holes or, “macs”, to form in the macula. A protein called cd59 normally helps prevent this from occurring. At Tufts University they are seeking a way to increase this protein in people with macular degeneration.

Rajendra Kumar-Singh: We plan to express the same protein but at higher levels on the cells that are normally getting damaged in AMD and theoretically we hope to be able to prevent the formation of these macs on these cells. When we use gene therapy we are in fact putting back in a normal version of the gene, such as the protein that is produced from that is now normal and allows the cell to revert to a normal, healthy looking or healthy functioning cell. We can potentially inject just once directly into the eye and that may serve as a therapeutic for the lifetime of the patient whether it be dry AMD or wet AMD. Science is all about solving problems and I would love to be the one to be able to solve this problem and provide some sort of therapies to people who otherwise might potentially go blind. And I think I’ll have fulfilled my role as a scientist if I can achieve that.

Rajendra Kumar-Singh, PhD, Professor of Ophthalmology and Neuroscience
Tufts University

Dean Bok, Phd, Distinguished Professor of Neurobiology and Ophthalmology
UCLA