Histopathologic study of variation in severity of retinitis pigmentosa due to the dominant rhodopsin mutation Pro23His.

To compare histopathologic findings in an autopsy eye of an 87-year-old woman with retinitis pigmentosa and the rhodopsin mutation Pro23His with findings in an autopsy eye of a 77-year-old female relative (first cousin) with retinitis pigmentosa and the same mutation. Histopathologic study. One eye from each patient was prepared for light and electron microscopy within 5 hours after death. Photoreceptor nuclear counts were performed. Photoreceptor degeneration and intraretinal bone spicule pigmentation were evident in both cases. The younger patient had more extensive photoreceptor loss and more intraretinal pigmentation than her older relative. A marked variation in the extent of retinal degeneration can be seen in two relatives with retinitis pigmentosa and rhodopsin, Pro23His. This study supports the idea that factors other than the primary gene defect are responsible for the severity of this condition.