['To assess the relative distribution in the cornea of amyloid and (beta)ig-h3 gene product in lattice corneal dystrophy type IIIA (LCD-IIIA).', 'Serial sections from the cornea of a patient with LCD-IIIA were subjected to either Congo red staining or immunohistochemistry employing an antibody to (beta)ig-h3. Also, genomic DNA was isolated from peripheral blood and used as a template for polymerase chain reaction to amplify all exons of (beta)ig-h3.', 'Exon 11 of (beta)ig-h3 was mutated (Pro501Thr). Subepithelial and intrastromal congophilic deposits exhibited a birefringency characteristic of amyloid. These regions of the tissue were also highly immunoreactive with the antibody to the (beta)ig-h3 gene product.'] Do amyloid and Pro501 Thr-mutated ( beta ) ig-h3 gene product colocalize in lattice corneal dystrophy type IIIA?