Rod and cone opsin mislocalization in an autopsy eye from a carrier of X-linked retinitis pigmentosa with a Gly436Asp mutation in the RPGR gene.

Abstract

We investigated whether opsin mislocalization occurs in photoreceptors in a female carrier of X-linked retinitis pigmentosa with a Gly436Asp mutation in the retinitis pigmentosa GTPase regulator gene (RPGR). Histologic findings in autopsy eyes from a carrier were compared with those from a normal female. Frozen retinal sections from the periphery of one eye of the carrier and the normal were stained with antibodies against either human red or green opsins, blue cone opsin, or rhodopsin and labeled with fluorochrome conjugated secondary antibodies. Cell nuclei were counterstained with Hoechst dye. Fellow eyes were evaluated with light microscopy. Fluorescent labeling showed mislocalized cone and rod opsins in photoreceptor cells only in the carrier. The carrier also showed some loss of photoreceptor nuclei. A defect in trafficking of opsins to outer segments exists in a carrier with the RPGR Gly436Asp mutation.