Grk1 Missense Mutations in Type II Oguchi Disease: A Literature Review.

Oguchi disease is a rare form of congenital stationary night blindness resulting from arrestin-1 (SAG) or rhodopsin kinase (GRK1) loss-of-function mutations. Unlike other congenital nyctalopias, patients with Oguchi disease can reach the dark-adapted state, albeit only after several hours of sustained darkness exposure. The mechanism underlying rhodopsin kinase dysfunction in Oguchi disease remains understudied. Previous research utilized the Grk1 knockout mice to reveal its role in phototransduction, the process that transduces light into neuronal signals in rod and cone photoreceptors. By studying Grk1 missense mutations via a knock-in approach, a more complete picture of the Oguchi disease mechanism involving GRK1 may be readily harvested. We summarize here the current knowledge on the Type II Oguchi disease with Grk1 missense mutations by focusing on the interaction of GRK1 with other proteins, and how these interactions influence dark adaptation. We call for more detailed analyses of GRK1 missense mutations in animal models, particularly V380D and L157P, to reveal novel disease mechanisms to gain further insight onto GRK1's action and function.