FTL and retinal degeneration: While similar observations were made in the human RP, the P34TL rabbit and the rd1-FTL mouse (Jones et al., 2016; Pfeiffer et al., 2016, Pfeiffer et al., 2020b; Greferath et al., 2015), to our knowledge, this is the first attempt to specifically quantify this variable GS immunoreactivity loss in late-stage retinal degeneration of the rd1 mouse.