RP can be inherited in an autosomal dominant, autosomal recessive, X-linked or Y-linked manner. X-linked RP can be either recessive, affecting primarily only males, or dominant, affecting both males and females, although males are usually more mildly affected. Some digenic (controlled by two genes) and mitochondrial forms have also been described. Genetic counseling depends on an accurate diagnosis, determination of the mode of inheritance in each family, and results of molecular genetic testing. Treatment
There is currently no cure for retinitis pigmentosa, but the efficacy and safety of various prospective treatments are currently being evaluated. The efficiency of various supplements, such as vitamin A, DHA, NAC, and lutein, in delaying disease progression remains an unresolved, yet prospective treatment option. Clinical trials investigating optic prosthetic devices, gene therapy mechanisms, and retinal sheet transplantations are active areas of study in the partial restoration of vision in retinitis pigmentosa patients. Stalling of disease
Studies have demonstrated the delay of rod photoreceptor degeneration by the daily intake of 15000 IU (equivalent to 4.5 mg) of vitamin A palmitate; thus, stalling disease progression in some patients. Recent investigations have shown that proper vitamin A supplementation can postpone blindness by up to 10 years (by reducing the 10% loss pa to 8.3% pa) in some patients in certain stages of the disease.
Researchers find that two molecules, rod-derived cone viability factor (RdCVF) and Nrf2, can protect cone photoreceptors in mouse models of retinitis pigmentosa.2016: RetroSense Therapeutics aimed to inject viruses with DNA from light-sensitive algae into the eyes of several blind people (who have retinitis pigmentosa). If successful, they will be able to see in black and white.In 2017 the FDA approved the gene therapy voretigene neparvovec to treat people with biallelic RPE65 mutation-associated retinal dystrophy.In 2020, a literature review estimated the experimental therapeutic technique called transcorneal electrical stimulation as "probably effective" (level B) in retinitis pigmentosa, based on the evidence available at that time.In 2021 an optogenetics application of the protein Channelrhodopsin in a human patient was reported with partial recovery of non-functional vision in a series of one patient only. They did not use standard protocol to measure visual improvement, but created their own criteria. The serendipitous discovery of the novel algal channelrhodopsin used came out of the 1000 Plant Genomes Project.