Two patterns of opacity in corneal dystrophy caused by the homozygous BIG-H3 R124H mutation

PURPOSE: To investigate the opacity pattern in corneas with an Arg124His (R 124H) homozygous mutation of the BIG-H3 gene. METHODS: Slit-lamp examination was performed on eight patients with corneal dystrophy resulting from a genetically confirmed BIG-H3 R124H homozygous m utation. The birthplaces of the patients also were determined. RESULTS: Slit,lamp examination disclosed two types of opacity patterns in c orneas with the BIG-H3 R124H homozygous mutation. Type I (n = 4) is a spot- like opacity present in the anterior stroma in which the lesions are conflu ent. Type I is the same pattern that previous reports have shown to be caus ed by the BIG-H3 R124H homozygous mutation. The type II corneal opacity pat tern (n = 4) is a reticular opacity in the anterior stroma. with round tran slucent spaces. Type II opacity has not been reported previously in associa tion with any corneal dystrophy. The patients with the type I opacity do no t share a common birthplace; however, interestingly, the patients with the type II opacity traced their origin to Tottori prefecture in western Japan. CONCLUSION: The BIG-H3 homozygous R124H mutation induces the development of two distinct patterns of corneal opacity, the recognition of which can est ablish an accurate diagnosis of corneal dystrophy caused by the homozygous BIG-H3 R124H mutation independent of genetic analysis. In addition, genetic factors or circumstantial influences other than the gene responsible for t he corneal dystrophy may influence the pattern of corneal opacity. (C) 2001 by Elsevier Science Inc. All rights reserved.