Biallelic rescue of CTG18.1 in two Fuchs endothelial corneal dystrophy–derived iPSC lines (SCTCi047-A-2, SCTCi046-A-2) following a two-step gene editing strategy

Fuchs endothelial corneal dystrophy (FECD) is an age-related condition distinguished by the degeneration of the corneal endothelium. An intronic CTG18.1 repeat in the transcription factor 4 ( TCF4 ) gene has been associated with a 78-fold increased risk of developing the disease when at least one copy of the CTG18.1 expands above 50 repeats. Employing patient-derived material, we applied a dual CRISPR/Cas9-mediated editing approach to rescue the expansion. Combining non-homologous end-joining (NHEJ) and homologous direct repair (HDR) events, we generated two FECD-derived +/+ (CTG) 8 induced pluripotent stem cell (iPSC) lines, which were then successfully characterized, providing relevant isogenic controls for disease-modelling purposes.