Genes in dizygote twins with Bowman layer corneal dystrophy

To report a de novo R124C mutation of transforming growth factor β-induced (TGFBI) gene in one of dizygotic twins with corneal dystrophy of the Bowman layer.

An 11-year-old boy was one of dizygotic twins and had a history of bilateral blurred vision and recurrent corneal erosion. Examination of the visual acuity demonstrated 20/40 in his each eye. Biomicroscopy showed bilaterally central corneal subepithelial opacities and some dot opacities in the superficial stroma. Anterior segment optical coherence tomography demonstrated most hyperreflective opacities at the subepithelial layer with some interspersed opacities in the superficial stroma. Confocal microscopy revealed irregular hyperreflective materials in the Bowman layer and the superficial stroma. Several rough filaments were found in the middle layer of stroma, corresponding to a feature of amyloid lattice. The corneas of his parents and dizygotic sister were clear. Sequencing of the TGFBI gene revealed an R124C mutation in the affected boy but not in his three healthy family members.

A de novo R124C mutation of the TGFBI gene may occur in one of dizygotic twins. Patients with an R124C mutation may have clinical features like corneal dystrophy of the Bowman layer. Confocal microscopy can be used to detect subclinical lattice lines, thereby facilitating differential diagnosis.