RPE65 and Leber congenital amaurosis: The same group reported in 1997 that loss of function mutations in the gene encoding for RPE65 cause certain forms of LCA (LCA2) [7], and in 1998 that RPE65 is essential for the trans-isomerization of all-trans retinal esters, as they accumulate in the RPE of the Rpe65-/- mouse [8].