Genetic Landscape of Nonsyndromic Retinitis Pigmentosa in Portugal

Inherited retinal degenerations (IRDs) comprise a heterogeneous group of disorders that cause severe vision loss or even blindness. With an estimated prevalence of 1:4000, Retinitis Pigmentosa (RP) is the most prevalent IRD. RP is characterized by progressive centripetal degeneration of rods, followed by degeneration of cone photoreceptors. Clinically, RP presents with nyctalopia of variable age of onset and progressive narrowing of the peripheral visual field. Most patients eventually experience some degree of central vision loss, leading to legal blindness. We have evaluated the most common RP-causing genes in a Portuguese IRD registry (IRD-PT, www.retina.com.pt ).