Our genes tell our cells which proteins to make. Our genes control our appearance, such as the color of our eyes and hair, and they determine much of our body’s makeup, like our blood type. Unfortunately, mutations in our genes can also cause disease and impair our quality of life. Furthermore, such mutations can be passed on to future generations, perpetuating these diseases and broadening their impact. These inherited diseases make up a leading category of illness and pose a tricky conundrum: how can we treat the actual underlying cause instead of just symptoms?

Treatments for inherited diseases have historically focused on treating the symptoms, while the underlying genetic cause remains out of reach. However, mapping the genome—detailing the sequences of genetic bases that make up our genetic code—has allowed for the advent of more specialized medicine that can target the actual genetic cause of a disease. With this advancement that allowed us to read our genetic code, we opened the door to actually fixing problems within it and fighting genetic diseases in a more powerful and targeted way.

Gene therapy is one such method that allows scientists to target the specific genetic cause of a disease. By replacing a defective gene with a healthy alternative or deactivating a mutated gene, gene therapy can provide healthy protein or prevent the production of deleterious protein. In doing so, a disease can be treated by targeting the specific underlying cause, allowing symptoms to subside.

In the Comparative Ophthalmology Laboratory, we develop gene therapy treatments for Progressive Retinal Atrophy (PRA), an inherited cause of retinal degeneration and blindness in cats and dogs. By packaging a healthy gene inside the shell of a virus, we can deliver this gene to the retina, resulting in the production of healthy protein. In doing so, we have shown that we can restore vision in animals. We can treat a disease by specifically treating the defect, instead of just the symptoms.

These studies are important not just for animals, but also for people. By showing that we can restore vision in companion animals, we can consider how this technology could also work to treat humans. As a result of such data in animals, human clinical trials are currently underway to test this technology in people. Theoretically, this form of treatment can be used for any inherited disease, and research is well underway to investigate its utility against many. Gene therapy is being tested as a treatment against various forms of cancer, the devastating respiratory illness Cystic Fibrosis, neurodegenerative conditions such as Parkinson’s disease and Alzheimer’s disease, and many others.

It was not long ago that working with the genome seemed like a futuristic dream. However, thanks to the mapping of the genome and developments that mapping made possible, such endeavors are now part of the present. Gene therapy that allows for more specific and powerful treatment of underlying genetic causes of disease is no longer a dream—it is a reality.