Analysis of TGFBI gene mutations in Chinese patients with corneal dystrophies and review of the literature

PURPOSE: To analyze human transforming growth factor b-induced (TGFBI) gene mutations in Chinese patients with corneal dystrophies (CDs). METHODS: Twenty-one families with corneal dystrophies were subjected to phenotypic and genotypic characterization. The corneal phenotypes of patients were documented by slit lamp photography. Mutation screening of the coding regions of TGFBI was performed by direct sequencing. An additional 43 families and 3 sporadic patients with TGFBI dystrophies from China reported in the literature were reviewed. RESULTS: Five mutations of TGFBI were identified in 21 families with CDs, including one novel small deletion mutation, c.△1838–1849 (p.Δ613–616VAEP), responsible for one variant lattice CD (LCD) family and 4 known mutations, R555W mutation for 10 granular cornea dystrophy type I (GCD1) families, R124H for 5 GCD type II (GCD2), R124C for 4 LCD1, and H626R for one variant LCD. In a cohort of Chinese patients (n=355) with TGFBI dystrophies from 64 families and 3 sporadic cases, 19 distinct mutations were found in several different CD subtypes. The 3 most common phenotypes were ranked as follows: GCD1, GCD2, and LCD1. Mutation hot spots at R124 and R555 occurred in >80% of these families. CONCLUSIONS: Our findings extend the mutational spectrum of TFGBI, and this is also the first extensively delineated TGFBI mutation profile associated with the various corneal dystrophies in the Chinese population.