Indeed, animal studies in NPC1-mutant mice demonstrated preclinical retinal degeneration and lipofuscin accumulation in the pigment epithelium and ganglion cells, electrodense inclusions in various cell types, photoreceptor defects, and hyperactivity of glial cells [42, 46], as well as optic nerve pallor and per macular grey discoloration [47]. This evidence concerns the gene NPC1 and retinal degeneration.