ZPR1 and retinitis pigmentosa 1: Additionally, the loss of expression in other vision-related proteins, such as Zpr1, SV2, HuC, and S100β, is not surprising due to previous studies showing that mutations in splicing factors can result in photoreceptor degeneration in diseases such as RP [15] where the most noticeable phenotype is a loss of photoreceptor cells [32].