X-linked retinitis pigmentosa (XLRP) is a severe form of inherited retinal degeneration that primarily affects the rod photoreceptors (Demirci et al., 2002). It typically causes an early-onset night blindness and loss of peripheral vision, often causing patients to become legally blind by the age of 30 to 40 years. In RP3, affected males have a severe phenotype, and carrier females show a wide spectrum of clinical features ranging from completely asymptomatic to severe RP (Jin et al., 2007). Mutation in the RPGR gene is believed to account for approximately 70% of XLRP (Vervoort et al., 2000). For a discussion of genetic heterogeneity of retinitis pigmentosa, see 268000.

Retinitis pigmentosa (RP), also designated rod-cone dystrophy, is characterized by initial night blindness due to rod dysfunction, with subsequent progressive constriction of visual fields, abnormal color vision, and eventual loss of central vision due to cone photoreceptor involvement (summary by El Shamieh et al., 2014). For a discussion of genetic heterogeneity of retinitis pigmentosa, see 268000.