Retinitis pigmentosa

Retinitis pigmentosa (RP), also known as rod-cone dystrophy, is a group of inherited retinal dystrophies characterized by progressive degeneration of photoreceptor cells in the retina, primarily affecting the rod photoreceptors first and subsequently the cone photoreceptors. It is one of the most common inherited retinal diseases. The condition affects the eye, specifically the retina — the light-sensitive tissue lining the back of the eye. RP is genetically heterogeneous, with mutations identified in more than 80 different genes, and can be inherited in autosomal dominant, autosomal recessive, or X-linked patterns. Digenic and mitochondrial forms have also been described. The hallmark symptoms of retinitis pigmentosa include night blindness (nyctalopia), which is often the earliest symptom, followed by progressive loss of peripheral (side) vision leading to tunnel vision, and eventually, in many cases, loss of central vision. Fundoscopic examination typically reveals the classic triad of bone-spicule pigmentation in the mid-peripheral retina, attenuation (narrowing) of retinal blood vessels, and waxy pallor of the optic disc. Additional ocular complications may include posterior subcapsular cataracts, cystoid macular edema, and, less commonly, vitreous cells. Electroretinography (ERG) shows reduced or absent rod and cone responses and is essential for diagnosis, particularly in early stages when fundus changes may be subtle. The age of onset and rate of progression vary considerably depending on the genetic subtype. X-linked forms tend to be the most severe, with earlier onset and faster progression, while autosomal dominant forms are often milder. Currently, there is no cure for most forms of RP. However, voretigene neparvovec (Luxturna) is an FDA-approved gene therapy for patients with biallelic RPE65 mutation-associated retinal dystrophy, which includes a subset of RP patients. Supportive measures include vitamin A palmitate supplementation (under medical supervision), use of low-vision aids, orientation and mobility training, and management of complications such as cataracts and macular edema. Retinal prosthetic devices and additional gene therapy approaches are under active investigation.

Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.

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