HISTOPATHOLOGIC AND IMMUNOHISTOCHEMICAL STUDY OF AN AUTOPSY EYE WITH X-LINKED CONE DEGENERATION

We performed a histopathologic and immunohistochemical study of eyes o btained at autopsy of an 84-year-old man from a family with X-linked c one degeneration in which affected members have a 6.5-kilobase deletio n in the red cone pigment gene. At his most recent ocular examination, at age 71 years, this patient had had a visual acuity of 20/200 OU, f undus changes suggestive of macular degeneration, borderline-normal fu ll-field rod electroretinograms, and profoundly reduced full-field con e electroretinograms. Histopathologic examination demonstrated marked loss of cone and rod photoreceptors and the retinal pigment epithelium in the central macula. The peripheral cone population was reduced, wh ile the peripheral rod population was relatively preserved, Immunohist ochemical examination with an antibody to both red and green cone opsi n and an antibody to blue cone opsin disclosed a prominent loss of the red and green cone population and preservation of the blue cone popul ation. These findings show that a defect in the red cone pigment gene can result in extensive degeneration of the red and green cone populat ion across the retina.