The relationship between granular, lattice type 1, and Avellino corneal dystrophies. A histopathologic study
R. Folberg, E. M. Stone, V. C. Sheffield and W. D. Mathers
Department of Ophthalmology, University of Iowa, Iowa City.
Three stromal corneal dystrophies (granular, lattice type 1, and Avellino)
were recently mapped to a single locus on chromosome 5. This study was
conducted to determine if there is histologic evidence to support the
allelic relationship suggested by the genetic studies. We examined 23
corneal buttons from the two families with lattice dystrophy and 13 corneal
buttons from the two families with granular dystrophy who were involved in
the chromosomal linkage studies. In the two families with clinically
typical granular dystrophy, one corneal button also contained focal amyloid
deposits. In both families with clinically typical lattice dystrophy type
1, we found evidence of granular deposits. The genetic linkage studies
demonstrate only that the disease-causing mutations for these three stromal
dystrophies share the same genetic locus. However, the evidence of
histologic overlap strongly suggests that these dystrophies are caused by
mutations within the same gene.
