This study was undertaken to identify βig-h3 gene mutations in Japanese patients with granular corneal dystrophy (GCD), Avellino corneal dystrophy (ACD), lattice corneal dystrophy (LCD), and Reis-Bücklers' corneal dystrophy (RBCD). R124H, R124C, R555W, and R555Q mutations have been reported in Europe to cause ACD, LCD type I, GCD, and RBCD, respectively.
In total, 91 Japanese patients who had been clinically diagnosed with GCD, LCD, or RBCD were investigated to determine whether they had mutations in the βig-h3 gene. Genomic DNA was amplified using the polymerase chain reaction and analyzed using single-strand conformation polymorphism techniques. Mutations were identified using the direct sequencing method.
In 68 unrelated patients who had been diagnosed with GCD, 62 patients (91%) were found to have the R124H mutation, which has been reported to cause ACD, whereas only six patients (9%) had the R555W mutation. In LCD patients, 10 patients with type I disease had the R124C mutation, and 10 patients with type IIIA disease had a P501T mutation. One patient with atypical LCD had an L527R mutation. In two patients with RBCD, one had an R555Q mutation and the other patient with geographic opacities was found to have an R124L mutation.
Depending on the specific mutation in the βig-h3 gene, the phenotypes of corneal dystrophy may differ. Our results indicate that assay of mutations in the βig-h3 gene is required to establish a correct diagnosis.
From the Department of Ophthalmology and Visual Science (S.Y., M.O., M.T., H.M., N.M., H.W., Y.I., Y.S., Y.T.), Osaka University Graduate School of Medicine, Osaka; and the Department of Ophthalmology (S.K.), Kyoto Prefectural University of Medicine, Kyoto, Japan.
Address correspondence and reprint requests to Dr. S. Yamamoto, Department of Ophthalmology and Visual Science, Osaka University Medical School, Room E7, 2-2 Yamada-oka, Suita, Osaka 565-0871, Japan. E-mail: firstname.lastname@example.org