Oxidative damage was shown to be associated with death of cones in retinitis pigmentosa, and of both photoreceptor cell types, in AMD.[166] Thioredoxin 1 (TRX1) in the retina plays a protective role against photooxidative damage.[167] Rod-derived cone viability factor (RdCVF) is a member of the thioredoxins family[168] and a trophic factor secreted by rods for maintaining cone viability and functionality.[169] In murine models, RdCVF is encoded by the Nxnl1 gene that also encodes for a second polypeptide, RdCVFL, by alternative splicing. This evidence concerns the gene NXNL1 and retinitis pigmentosa.