Retinitis pigmentosa 67

Retinitis pigmentosa (RP) is the name given to a group of hereditary retinal conditions in which degeneration of rod photoreceptors, responsible for vision under dark conditions, is more pronounced than that of cone photoreceptors, which mediate daylight vision. Individuals with RP typically experience night blindness at first, followed by progressive and unstoppable visual impairment in daytime conditions as well. Their visual fields become reduced gradually and sight is lost from the midperiphery to the periphery, then from the midperiphery to the center, resulting eventually in complete or near-complete blindness if left untreated. Most patients show intraretinal pigment in a bone-spicule configuration around the fundus periphery as well as retinal arteriolar attenuation, elevated final dark-adapted thresholds, and reduced and delayed electroretinograms. Autosomal recessive RP is the most common form of hereditary retinal degeneration in humans (summary by Nishiguchi et al., 2013). For a discussion of genetic heterogeneity of retinitis pigmentosa, see 268000. [from OMIM]