TGFBI mutational analysis in a New Zealand population of inherited corneal dystrophy patients

Aim The corneal dystrophies represent a group of clinically and genetically heterogeneous, inherited diseases, often resulting in bilateral opacification of the cornea, and may require penetrating keratoplasty. Mutations in the transforming growth factor beta-induced (TGFBI) gene segregate with a wide range of phenotypically heterogeneous corneal dystrophies. Many of the other dystrophies remain without molecular characterisation. This study aimed to characterise the molecular basis for corneal disease in a New Zealand population. Methods Nineteen unrelated individuals affected with a corneal dystrophy (granular, fleck, lattice, posterior polymorphous) and their family members were recruited, a pedigree obtained and their dystrophy extensively phenotyped. After informed consent, samples were taken for DNA extraction. PCR and sequencing of all coding exons of TGFBI was undertaken. Results All five patients with granular dystrophy had the R555W mutation, and H626P was identified in an intermediate dystrophy of Bowman layer pedigree. No other mutations were detected including in the stromal dystrophy cases. Conclusion Mutational analysis of TGFBI in a small population has identified sequence changes consistent with previously identified genotype-phenotype correlations. A new genotype-phenotype association was also characterised. No mutations were identified in some individuals/pedigrees suggesting greater genetic heterogeneity than is currently known in this group of disorders.