TCF4 and Fuchs endothelial corneal dystrophy: In this study we aimed to investigate if the TCF4 (CTG)n expansion (n > 40) (TCF4+), present in the majority of FECD patients affects the mRNA expression of TCF4 transcripts spanning over the CTG18.1 or transcripts with TSS immediately at the 3′-end of the (CTG)n.