A new mutation (A546T) of the beta ig-h3 gene responsible for a French lattice corneal dystrophy type IIIA

PURPOSE: To characterize the beta ig-h3 gene defect in a French family affe cted with lattice corneal dystrophy type IIIA (LCDIIIA). METHODS: Histologic examination was performed from corneal buttons of two p atients. Genomic DNA was extracted from leukocytes, and exons of the beta i g-h3 gene were amplified by polymerase chain reaction to be directly sequen ced. RESULTS: Numerous deposits were evident in the stroma and beneath the Bowma n membrane, which had all the features of amyloid deposits. Analysis of exo n 12 revealed a heterozygous G to A transition on codon 546. CONCLUSION: In contrast to Japanese patients, these French patients affecte d with LCDIIIA carry a distinct mutation of the beta ig-h3 gene (A546T inst ead of P501T). Therefore, it is unclear whether different mutations could r esult in the same dystrophy or whether we are dealing with clinical heterog eneity of LCDIIIA. (Am J Ophthalmol 2000;129:248-251. (C) 2000 by Elsevier Science Inc. All rights reserved.).