Histopathologic study of X-linked cone-rod dystrophy (CORDX1) caused by a mutation in the RPGR exon ORF15

PURPOSE: To evaluate the donor retina of a patient with X-linked cone-rod dystrophy caused by an RPGR exon ORF15 mutation. DESIGN: Histopathologic study of the retina. METHODS: The eye of a 69-year,old man was fixed at 1.6 hours Postmortem and processed for histopathology and immunocytochemistry. RESULTS: Grossly, the macula was atrophic with a bull's, eye appearance. The remaining retina showed postmortem edema but no intraretinal pigment. Microscopically, the macular retinal pigment epithelium was absent focally and had pigmentary changes elsewhere. Cones and rods were absent from the perifovea and reduced with shortened outer segments elsewhere in the macula. In the remainder of the retina, cones but not rods were reduced and all photoreceptor outer segments were shortened. CONCLUSIONS: The abnormalities in both cone and rod photoreceptors confirm the importance of RPGR in both cell types but leaves unresolved how various exon ORF15 mutations lead to different clinical phenotypes.