Mutations in arrestin gene (SAG, S-antigen; OMIM:181031) were first discovered in Japanese patients (Oguchi disease type 1) [1], later on, mutations involving the rhodopsin kinase gene (GRK1; OMIM:180381) were implicated in European patients (Oguchi disease type 2) [2]. The gene discussed is GRK1; the disease is Oguchi disease-1.