Retinitis pigmentosa 2 is one of several different forms of retinitis pigmentosa (RP), a genetic eye condition that leads to vision loss. RP is caused by the loss of light receptor cells (photoreceptors) that are located in the back of the eye (retina). The photoreceptors, which send signals from the eye to the brain, are made up of rods and cones. The rods help with vision in lower light as well as side (peripheral) vision. The cones help with vision in bright light. In RP, the rods start to go away first, which causes a person to have poor night vision, which usually starts in childhood. As time goes on, a person starts to have poor peripheral vision, followed by vision only in the center (tunnel vision) and then total blindness. The progression of these symptoms usually takes several years. Retinitis pigmentosa 2 usually affects males.
Retinitis pigmentosa 2 is caused by a change (mutation) in the RP2 gene, which is located on the X chromosome, and is inherited in an x-linked recessive manner. Males have one X chromosome (one copy of the RP2 gene) and females have two X chromosomes (two copies of the RP2 gene). If a male has a mutation in their only RP2 gene copy, they do not have a working copy of the gene and will have retinitis pigmentosa. If females have a mutation in one of their two copies of the RP2 gene, they have another working copy as backup and typically will not have retinitis pigmentosa.
RP can be diagnosed with the use of vision tests and eye exams that show poor vision, rod dysfunction, and loss of photoreceptor function. There is currently not a cure for RP, but there are some medications available that may help slow the progress of the disease. If your child has been diagnosed with RP, talk to their doctor about current treatment options. Support groups may provide additional information and connect you with others affected by RP.