RHO and Alzheimer disease: Common genes implicated in autosomal dominant RP include the RHO gene (20–30% of AD RP cases), which encodes for rhodopsin and can lead to gain-of-function mutation in which large amounts of misfolded rhodopsin overwhelm the ubiquitin proteasome system and leads to cell toxicity [41]; the PRPF31 gene (10%), a pre-mRNA slicing factor producing high levels of alternatively spliced transcripts in photoreceptors [41]; and the RP1 gene (10%), a microtubule-associated protein in the outer segment disc [40].