Last update 3/2008

Eye Research Network   Guide to Retinitis Pigmentosa Kenneth P. Mitton, Ph.D., Editor

Many RP conditions have been mapped to a specific area of a specific human chromosome but the actual gene involved is not certain. Some RP families have had the mutation mapped and then found in a specific gene encoding a specific protein. Some of these mutations involve proteins that make up part ot the light detection machinery of the rod-photoreceptor cell, such as Rhodopsin protein. Rhodopsin is the protein that first detects a packet of light energy to start the visual signaling all the way into the brain. Many other mutations have been mapped to other proteins in the visual transduction cascade that are downstream of rhodopsin. More recently, laboratories have found mutations in proteins that are Transcription Factors which have the job of "turning on" the Rhodopsin gene in rod-photoreceptors. 

(In the Mitton laboratory, we map and study the control networds involving these transcription factors. Our research helps us understand how these networks function and why mutations disrupt the normal system to cause RP and other retinal degenerations.)

In addition to research all over the world to map the mutations in RP families, there is great interest in trying to slow the degeneration or rescue the vision by protecting the cone-cells. Even when the mutation affects a protein that is only in rod-cells, ie. Rhodopsin, the massive die-off of rod-cells seems to trigger a death of cone-cells as well. Future treatments may initially target the rescue of cone-cells in the retina (you would be able to see OK in daylite, and see color!). One day, hopefully we will also have gene-based therapies to prevent the loss of rod cells in the first place.   

Kenneth P. Mitton, PhD, 2008