Retinitis pigmentosa (RP) refers to a group of related eye disorders that cause progressive vision loss. RP is a rare inherited retinal dystrophy that causes progressive loss of vision due to loss of the photoreceptors and spots of black pigmentation of the retinal pigment epithelium. RP can lead to total blindness after decades.
More than 3,000 mutations in over 60 different genes or loci are currently known to cause non-syndromic RP. More than 20 of these genes are associated with the autosomal dominant form of the disorder. The most common mutation responsible for the autosomal dominant form of RP are in the RHO gene. The most common mutations associated with the autosomal recessive form of RP are within the USH2A gene. As for the X-linked form of RP, mutations in the RPGR and RP2 genes account for most cases.
The most common, and often only, symptom of RP is progressive vision loss beginning with night blindness and eventually leading to central vision loss. Central vision loss may occur at any age as a result of macular edema or photoreceptor loss. Cataracts are a common symptom and severity is age dependent. Another possible symptom is reduced colour vision.
Currently, treatment mainly involves slowing the progression of the disease. Treatments include Vitamin A palmitate and lutein-DHA, oral acetazolamide or topical dorzolamide to reduce cystoid macular edema. Lens extraction can help when cataracts reduce visual acuity. Specialised sunglasses and optical aids can also be used to treat symptoms
