Pre-existing or emerging mutations that contribute to rod photoreceptor degeneration in retinitis pigmentosa are passed down through familial lines; thus, allowing certain RP cases to be concentrated to specific geographical regions with an ancestral history of the disease. Several hereditary studies have been performed to determine the varying prevalence rates in Maine (USA), Birmingham (England), Switzerland (affects 1/7000), Denmark (affects 1/2500), and Norway. Navajo Indians display an elevated rate of RP inheritance as well, which is estimated as affecting 1 in 1878 individuals. Despite the increased frequency of RP within specific familial lines, the disease is considered non-discriminatory and tends to equally affect all world populations. Research
Future treatments may involve retinal transplants, artificial retinal implants, gene therapy, stem cells, nutritional supplements, and/or drug therapies. 2012: Scientists at the University of Miami Bascom Palmer Eye Institute presented data showing protection of photoreceptors in an animal model when eyes were injected with mesencephalic astrocyte-derived neurotrophic factor (MANF). Researchers at the University of California, Berkeley were able to restore vision to blind mice by exploiting a "photoswitch" that activates retinal ganglion cells in animals with damaged rod and cone cells.2015: A study by Bakondi et al. at Cedars-Sinai Medical Center showed that CRISPR/Cas9 can be used to treat rats with the autosomal dominant form of retinitis pigmentosa.
Retinitis pigmentosa (RP) is a genetic disorder of the eyes that causes loss of vision. Symptoms include trouble seeing at night and decreasing peripheral vision (side and upper or lower visual field). As peripheral vision worsens, people may experience "tunnel vision". Complete blindness is uncommon. Onset of symptoms is generally gradual and often begins in childhood.Retinitis pigmentosa is generally inherited from one or both parents or rarely it can be newly evolved from a miscoding during DNA division. It is caused by genetic miscoding of proteins in one of more than 300 genes involved. The underlying mechanism involves the progressive loss of rod photoreceptor cells that line the retina of the eyeball. The rod cells secrete a neuroprotective substance (Rod-derived cone viability factor, RdCVF) that protects the cone cells from apoptosis (cell death). However, when the rod cells die, this substance is no longer provided. This is generally followed by the loss of cone photoreceptor cells. Diagnosis is by eye examination of the retina finding dark pigment deposits caused by the rupture of the underlying retinal pigmented epithelial cells, given that these cells contain a pigment known as melanin. Other supportive testing may include the electroretinogram (ERG), visual field testing (VFT), ocular coherence tomography (OCT) and DNA testing to determine the gene responsible for a persons particular type of RP (now called Inherited Retinal Dystrophy (IRD).There is currently no cure for retinitis pigmentosa. Efforts to manage the problem may include the use of low vision aids, portable lighting, or orientation and mobility training.