ABCA4 and Cone rod dystrophy: In another study, Tucker et al. [2] reported the discovery of a new pathogenic variant of USH2A in another patient with rod-cone dystrophy who was presumed heterozygous for a pathogenic variant in ABCA4 and USH2A. The second possibly disease-causing variant was found in intron 40 of USH2A, and this was confirmed by real-time PCR of patient-specific iPSC-derived photoreceptor precursor cells.