Purpose: To determine amyloid deposition in the corneas of granular corneal dystrophy in Japanese patients.
Methods: Eight Japanese patients (10 eyes) with a clinical diagnosis of granular corneal dystrophy were investigated clinically and histologically. Each specimen obtained at surgery was stained with hematoxylin-eosin, Masson trichrome or Mallory, and Congo red stain. Amyloid deposit was identified by birefringence and dichroism under cross-polarized light after staining with Congo red.
Results: Seven (70%) of the 10 corneal buttons (six of eight patients) had amyloid deposits, as shown by Congo red staining with birefringence and dichroism. Of the six amyloid-positive patients, two patients (who were siblings) showed discrete gray-white corneal deposits with additional linear deposits. This finding is typical of Avellino corneal dystrophy. The corneas of the remaining four patients showed the discrete deposits typical of granular dystrophy. Some of them showed a few whitish fusiform and stellate opacities in the mid stroma, suggestive of Avellino corneal dystrophy.
Conclusion: The high frequency of amyloid deposits in Japanese patients with granular corneal dystrophy may be caused by an allelic heterogeneity of the gene.