Human experiments involving gene therapy must first be reviewed and approved by the National Institute of Health’s (NIH) Office of Recombinant DNA Activities (ORDA)/ Recombinant DNA Advisory Committee (RAC) and by the Food and Drug Administration (FDA). In addition to approval of an Investigational New Drug Application (IND) from the FDA, approval from an Institutional Review Board (IRB) where the study will take place must also be obtained.
We would also need to recruit subjects who would be willing to be pioneers in the cure for red-green color blindness; that is, willing to accept the risks involved knowing that it may not work.
Risks:
• Gene therapy for red-green color blindness may not work in humans as well as it does in the monkeys.
• Side effects of subretinal injections can include irritation or infection, in addition to the risks of permanent retinal detachment and blindness at the injection site.
• There could be adverse psychological effects associated with suddenly being able to see new colors and learning how to categorize them.
Benefits:
• Gene therapy might, indeed, work to cure red-green color blindness and allow patients to see the world in a whole new way.
• As color blindness is a vision disorder that does not involve retinal degeneration, attempting its treatment in humans will allow us to understand the full potential of gene therapy to restore visual capacities, as well as to develop additional therapies for a broad range of retinal diseases.
• Results obtained from gene therapy for red-green color blindness will provide a wealth of information about the how the human visual system works.
The same gene therapy virus vector and injection procedures are currently being used in human gene therapy trials for a blinding disorder known as Leber’s congenital amaurosis, or LCA. Thus far, no serious adverse events have been reported, even after one year post-treatment. A key difference in our experiments for color blindness is the therapeutic gene that is carried by the virus vector. Because a human visual pigment gene was used to replace the missing visual pigment of the monkeys, and no adverse side effects have been observed, we are optimistic that this transgene will also be safe to use in humans. The most critical barrier in moving the treatment forward will be insuring its safety for human patients.
While red-green color blindness is generally not considered to be a debilitating visual disorder, many affected individuals would disagree. Normal color vision is required for employment as a police officer, fire fighter, commercial/public transit driver, or pilot. In other professions, the requirement for normal color vision is not as obvious, and some spend years training for careers as designers, geologists, chemists, or ophthalmologists before being excluded by their color vision deficiency. Everyday difficulties associated with red-green color blindness are presented in the slide show, “colorblind world.”