Heterogeneity in macular corneal dystrophy
D. P. Edward, B. Y. Yue, J. Sugar, E. J. Thonar, N. SunderRaj, E. L. Stock and M. O. Tso
Department of Ophthalmology, University of Illinois College of Medicine, Chicago 60612.
Macular corneal dystrophy is an autosomal recessive disorder in which
abnormal deposits in the corneal stroma have been identified. We examined
the corneal buttons of 12 patients, who had clinical features of macular
dystrophy, by histochemical staining, transmission electron microscopy, and
immunohistochemical techniques. All corneas exhibited positive staining
with Muller Mowry's colloidal iron. Using monoclonal antibodies 1/20/5-D-4,
J-10, J-19, and J-36 that recognize specific sites on the sulfated keratan
sulfate molecule, we stained corneal sections by an
avidin-biotin-peroxidase complex method and identified two groups of
macular corneal dystrophy. One group consisting of four corneas reacted
positively with all four antibodies, and the other group consisting of
eight corneas did not react with any of the antibodies used. These results
confirmed those recently presented by Yang et al that there may be
subgroups of macular dystrophy that can be identified by
immunohistochemical methods. Also, serum levels of sulfated keratan sulfate
were determined in seven patients. One patient who displayed a normal level
of serum keratan sulfate had positive corneal immunoreactivity. Of the six
patients who lacked serum keratan sulfate, four showed negative and two had
positive corneal immunostaining, suggesting at least three subgroups in the
disease. An attempt was made to correlate the clinical features,
histochemical-staining characteristics, and ultrastructural morphology with
the immunoreactivity to keratan sulfate antibodies, but no correlations
could be made.
