Question: How many people are affected by retinitis pigmentosa ?
Answer: Retinitis pigmentosa is one of the most common inherited diseases of the retina (retinopathies). It is estimated to affect 1 in 3,500 to 1 in 4,000 people in the United States and Europe.
Source: GHR

Question: What are the genetic changes related to retinitis pigmentosa ?
Answer: Mutations in more than 60 genes are known to cause nonsyndromic retinitis pigmentosa. More than 20 of these genes are associated with the autosomal dominant form of the disorder. Mutations in the RHO gene are the most common cause of autosomal dominant retinitis pigmentosa, accounting for 20 to 30 percent of all cases. At least 35 genes have been associated with the autosomal recessive form of the disorder. The most common of these is USH2A; mutations in this gene are responsible for 10 to 15 percent of all cases of autosomal recessive retinitis pigmentosa. Changes in at least six genes are thought to cause the X-linked form of the disorder. Together, mutations in the RPGR and RP2 genes account for most cases of X-linked retinitis pigmentosa. The genes associated with retinitis pigmentosa play essential roles in the structure and function of specialized light receptor cells (photoreceptors) in the retina. The retina contains two types of photoreceptors, rods and cones. Rods are responsible for vision in low light, while cones provide vision in bright light, including color vision. Mutations in any of the genes responsible for retinitis pigmentosa lead to a gradual loss of rods and cones in the retina. The progressive degeneration of these cells causes the characteristic pattern of vision loss that occurs in people with retinitis pigmentosa. Rods typically break down before cones, which is why night vision impairment is usually the first sign of the disorder. Daytime vision is disrupted later, as both rods and cones are lost. Some of the genes associated with retinitis pigmentosa are also associated with other eye diseases, including a condition called cone-rod dystrophy. Cone-rod dystrophy has signs and symptoms similar to those of retinitis pigmentosa. However, cone-rod dystrophy is characterized by deterioration of the cones first, followed by the rods, so daylight and color vision are affected before night vision.
Source: GHR

Question: What are the treatments for retinitis pigmentosa ?
Answer: These resources address the diagnosis or management of retinitis pigmentosa: - American Foundation for the Blind: Living with Vision Loss - Foundation Fighting Blindness: Treatment of Retinitis Pigmentosa - Gene Review: Gene Review: Retinitis Pigmentosa Overview - Genetic Testing Registry: Retinitis pigmentosa - RP Fighting Blindness: Treatment of Retinitis Pigmentosa These resources from MedlinePlus offer information about the diagnosis and management of various health conditions: - Diagnostic Tests - Drug Therapy - Surgery and Rehabilitation - Genetic Counseling - Palliative Care
Source: GHR