Retinitis pigmentosa is a genetically heterogenous group of inherited retinal dystrophies mainly characterised by predominant rod impairment initially followed by subsequent cone dysfunction. Over 80 genes have been attributed to RP resulting in significant clinical heterogeneity. 20-30% of patients have syndromic RP. The most common are Usher syndrome and Bardet-Biedl syndrome.

Usher syndrome is a group of inherited disorders characterised by a combination of sensorineural hearing loss and retinitis pigmentosa.

RNA is involved in protein production from DNA in human cells. Mutations in DNA can be passed down to RNA, and a non-functional protein might be produced. RNA therapies target these "mistakes" in the RNA so that a normal functional protein can be produced instead.