Uncovering the profile of mutations of transforming growth factor beta-induced gene in Chinese corneal dystrophy patients.

aimTo uncover the mutations profile of transforming growth factor beta-induced (TGFBI) gene in Chinese corneal dystrophy patients and further investigate the characteristics of genotype-phenotype correlations.

methodsForty-two subjects (6 unrelated families including 15 patients and 8 unaffected members, and 19 sporadic patients) of Chinese origin 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.

resultsWe detected four corneal dystrophy types. The most frequent phenotypes were granular corneal dystrophy (GCD) (including 3 families and 8 sporadic patients) and lattice corneal dystrophy (LCD) (including 2 families and 9 sporadic patients). The next phenotypes were corneal dystrophy of Bowman layer (CDB) (1 family and 1 sporadic patient) and epithelial basement membrane dystrophy (EBMD) (1 sporadic patient). Six distinct mutations responsible for TGFBI corneal dystrophies were identified in 30 individuals with corneal dystrophies. Those were, p.R124H mutation in 1 family and 2 sporadic patients with GCD, p.R555W mutation in 2 families and 3 sporadic patients with GCD, p.R124C mutation in 2 families and 7 sporadic patients with LCD, p.A620D mutation in 1 sporadic patient with LCD, p.H626R mutation in 1 sporadic patient with LCD, and p.R555Q in 1 family and 1 sporadic patient with CDB. No mutation was detected in the remaining 3 atypical GCD patients and 1 EBMD patient.

conclusionGCD and LCD are the most frequent phenotypes in Chinese population. R555W was the most common mutation for GCD; R124C was the most common mutation for LCD. Our findings extend the mutational spectrum of TFGBI, and this is the extensively delineated TGFBI mutation profile associated with the various corneal dystrophies in the Chinese population.