The selective abundance of poly(CUG) RNA foci in FECD corneal endothelial cells compared with a non-target cell type (fibroblasts) (Figs. 2 and 3) suggests that TCF4 poly(CUG) transcripts predominantly accumulate in the corneal endothelium, leading to FECD pathogenesis. This evidence concerns the gene TCF4 and Fuchs endothelial corneal dystrophy.