Abstract
Purpose: :
To identify the gene defect causing X-linked congenital stationary night blindness (CSNB) with myopia in a male whose ocular findings and electroretinograms (ERGs) were previously described (Hill, Arbel, and Berson, AJO 78:127-136, 1974) and to define the histopathologic retinal changes in his autopsy eyes.
Methods: :
Autopsy eyes were obtained from an 87 year-old male with CSNB and high myopia who died of congestive heart failure. Leukocyte DNA from this patient was screened for mutations in the NYX gene since mutations in the NYX gene have been associated with this condition. His right eye was fixed 24 hours after death in 2.5% glutaraldehyde and 1% formaldehyde for ultrastructural studies and the left eye in buffered 4% formaldehyde for immunocytochemistry. Autopsy eyes from an 84 year-old unaffected male with an identical post-mortem interval were similarly prepared for histopathologic comparison.
Results: :
DNA sequencing revealed a novel Leu202Pro mutation of the NYX gene. Light microscopic and ultrastructural examination of the midperiphery of his right eye showed a disorganized, vacuolated outer plexiform layer and loss of some cells in the inner nuclear layer. Cell loss was seen in the outer nuclear layer in this region also. The macula appeared unaffected. Cone and rod inner and outer segments appeared normal. These findings correlate well with previously reported ERGs by Hill et. al. which showed preservation of the rod a-wave and loss of the rod b-wave. Immunocytochemical studies are in progress to further define the observed inner retinal pathology.
Conclusions: :
To our knowledge this is the first histopatholgic report of a male with X-linked CSNB with myopia with a Leu202Pro missense mutation in the NYX gene. We show that previous ERGs recorded from this patient are consistent with the current histologic abnormalities seen in the inner retinal layers with relative preservation of the outer retinal layer.
Keywords: pathology: human • retina: proximal (bipolar, amacrine, and ganglion cells) • mutations