ABCA4 and age-related macular degeneration: An understanding into retinal cholesterol metabolism comes from inquiries on the pathobiological nature of the retinal phenotype of ATP-binding cassette, subfamily A, member 4 (Abca4) knockout mice, which lead to discoveries on a vital role of dysregulated cholesterol trafficking as an important pathobiological event in the development of AMD-like pathologies in this model (116).