Oguchi Disease, Retinitis Pigmentosa, and the Phototransduction Pathway

Abstract

Oguchi disease is a form of retinal dysfunction in which congenital night blindness is accompanied by a light-dependent discoloration of the fundus, extremely slow dark adaptation and an abnormal rod electroretinogram. This autosomal recessive condition is generally considered to be non-progressive however Oguchi disease and progressive retinal pigmentary degeneration or congenital stationary night blindness has occurred in the same families and even in the same patients. Oguchi disease may therefore represent a disorder involving features of both congenital stationary night blindness and retinitis pigmentosa. Here we summarise molecular genetic analyses which indicate that mutations in the arrestin gene are responsible for at least some cases of Oguchi disease in the Indian and Japanese populations. We speculate that the light-dependent fundus discoloration characteristic of Oguchi disease may reflect hyper-activity of the phototransduction pathway resulting from failure of arrestin to bind to and quench light-activated rhodopsin.