TCF4 and Fuchs endothelial corneal dystrophy: Although the frequency of CTG18.1 TNR expansions in TCF4 is not known for our samples, given its high linkage disequilibrium with rs613872 (Mootha et al. 2014) and previous studies in the German population (Foja et al. 2017), it can be assumed to be the primary causal variant for FECD.