Figure 1. Topological organization of the ABCA4 protein. The pictorial representation shows the domains of ABCA4, as follows: transmembrane domain 1 (TMD1) aa 22–45/648–854, exocytoplasmic domain 1 (ECD1) aa 62–646, nucleotide-binding domain 1 (NBD1) aa 914–1152, regulatory domain 1 (RD1) aa 1153–1280, transmembrane domain 2 (TMD2) aa 1375–1395/1665–1898, exocytoplasmic domain 2 (ECD2) aa 1395–1665, nucleotide-binding domain 2 (NBD2) aa 1916–2163, and regulatory domain 2 (RD2) aa 2164–2237. Variations in our cohort are depicted in the structure. (Created with BioRender.com.).