Abca4, localized on human chromosome 1p21, exists in AMD.279 Variants of Abca4 associated with AMD include D2177N, G1961E, and R1898H.279 The Abca4 protein is an ATP-binding cassette transporter 4 and is responsible for the elimination of metabolic products from phototransduction or lipids. This evidence concerns the gene ABCA4 and age-related macular degeneration.