CNGA3 and achromatopsia: Genetic variants responsible for the disease have been identified in 6 genes—CNGA3 and CNGB3 (mutated in approximately 70% of all ACHM cases), GNAT2, PDE6C, PDE6H, and ATF6—all encoding for components of the cone phototransduction cascade with the exception of ATF6, which plays a role in the regulation of the unfolded protein response and endoplasmic reticulum homeostasis [2,3,4].