Conversely, Foja et al. using a single TaqMan probe complementary to an exon spanning region in close proximity to the CTG18.1 region found reduced levels of TCF4 expression within corneal endothelial explants derived from expansion-positive (≥50 repeats) FECD patients when compared to controls (<50 repeats) (Foja et al., 2017). This evidence concerns the gene TCF4 and Fuchs endothelial corneal dystrophy.