If TCF4plays a role in familial FECD, further research is needed todiscover the mutation(s)within TCF4 that segregate with disease in families that showevidence of linkage to FCD2. l. Until such a causative mutation(s)is identified, restraint needs to be exercised in not drawing premature conclusionsthat a causal link between the TCF4 protein and FECD has been identified. This evidence concerns the gene TCF4 and Fuchs endothelial corneal dystrophy.