,49,54 LCA variants, on the other hand, prevent proper formation of the RetGC:GCAP complex or/and reduction of RetGC1 catalytic activity32,35 leading to reduced levels of cGMP, failure to open the proper fraction of the CNG channels, and a consequent reduction of the ERG a-wave.8 This evidence concerns the gene GUCY2D and Leber congenital amaurosis.