They detected intronic TNR expansion-containing TCF4 transcripts (hereafter referred to as poly(CUG)n TCF4 transcripts) in three FECD patients with a confirmed intronic TNR expansion in the TCF4 gene, while expression of normal TCF4 transcripts was found in one FECD patient and all controls without intronic TNR expansion in TCF4. Here, TCF4 is linked to Fuchs endothelial corneal dystrophy.