ABCA4 and retinitis pigmentosa 1: For example mutations of the PROM1 gene have been shown to result in retinitis pigmentosa (RP) but also in Stargardt disease; of interest, in addition, is the broad spectrum of diseases seen in patients with ABCA4 retinopathies, from Stargardt disease/fundus flavimaculatus, to cone–rod dystrophy to RP.