ABCA4 and retinitis pigmentosa 19: Mutations in ABCA4 (MIM 601691; transcript number ENSP 00000359245.3), also known as ABCR, are responsible for most cases with autosomal recessive STGD, and are also implicated in other retinal degenerative diseases such as retinitis pigmentosa type 19, cone-rod dystrophy, and age-related macular degeneration [3,4].