DMPK and myotonic dystrophy type 1: Identical foci have been found in the corneal endothelium of FECD patients harboring TCF4 TNR expansion.13 A less likely explanation for our findings is that the cosegregation of DM1 and FECD in the absence of TCF4 repeat expansion is purely coincidental or that the FECD is induced by a previously unrecognized genetic variant in linkage disequilibrium with the causative DMPK expansion.