Summary 4

Dolgin E. Color blindness corrected by gene therapy. Nature [Internet]. 2009 Sept 16 [cited 2009 Sept 17]; doi:10.1038/news.2009.921 . Available from: http://www.nature.com.mutex.gmu.edu/news/2009/090916/full/news.2009.921.html

Jay Neitz of the University of Washington in Seattle and his colleagues conducted an experiment on red green color blindness. Color blindness occurs because there is a missing gene for either red or green on the cone cells on the retina. Squirrel monkeys have to have both of the versions of the opsin gene in order to see in full color. All male squirrel monkeys are color blind because the opsin genes are each carried on only one x chromosome. This allows most of the females to see in full color, but all of the males must be colorblind. The researchers attached the human red opsin gene to a viral vector and injected it behind the squirrel monkeys’ retinas. Within 20 weeks, the monkeys were able to see the color red.
This study suggests that color blindness in humans could be corrected. Previously, researchers weren’t certain if the brains of color blind individuals were unable to interpret or receive the signals from the cone cells. Now they know that correcting the missing gene at only the cone cell level can correct the color blindness. The main concern is that color blind humans often have excellent vision. Researchers are concerned that any alteration might affect the vision.