ABCA4 and Stargardt disease: Equine infectious anemia virus (EIAV) 3rd generation lentivirus-based gene therapies for the MYO7A gene (6645 bp; 2215 amino acid) and the ABCA4 gene (6819 bp; 2273 amino acids) delivered to photoreceptors have been in clinical trials for Usher syndrome type I and Stargardt disease (NCT01367444; NCT01505062) since 2011/2012, respectively.