PDE6H and inherited retinal dystrophy: This explains why pathogenic variants in PDE6A (OMIM #180071), PDE6B (OMIM #180072) and PDE6G (OMIM #180073) cause predominantly rod-involving retinal dystrophies, whereas pathogenic variants in PDE6C and PDE6H (OMIM #600827 and #601190) lead to retinal dystrophies which predominantly affect cones17–19.