Prevalence of transforming growth factor β–induced gene corneal dystrophies in Chinese refractive surgery candidates

Purpose To determine the prevalence of the transforming growth factor (TGF) β–induced gene corneal dystrophies in refractive surgery candidates in China. Setting Five hospitals in China. Design Prospective case series. Method Refractive surgical candidates from 5 preselected eye hospitals/centers in China were recruited after providing informed consent. All patients had slitlamp biomicroscopy and collection of a buccal swab as a source of DNA for screening of the TGF β–induced gene for the 5 most common mutations associated with Reis-Buckler corneal dystrophy, Thiel-Behnke corneal dystrophy, granular corneal dystrophy type 1, granular corneal dystrophy type 2, and lattice corneal dystrophy type 1. Results Of the 2068 refractive surgery candidates analyzed, 4 had corneal opacities in both eyes on slitlamp examination. Screening for the TGF β–induced gene found the heterozygous p.R124H mutation associated with granular corneal dystrophy type 2 in each of the 4 individuals with corneal opacities as well as in a fifth individual who did not have any corneal opacities, for a prevalence of 0.24%. Exacerbation of dystrophic corneal deposition developed after laser refractive surgery in 2 individuals who did not have preoperative TGF β–induced gene screening. Conclusions The prevalence of the TGF β–induced gene corneal dystrophies in Chinese refractive surgery candidates was estimated to be approximately 0.24%. Genetic testing is recommended to identify and exclude from candidacy all individuals with a TGF β–induced gene dystrophy before elective keratorefractive surgery to avoid causing accelerated postoperative dystrophic deposition.