This approach may be suitable for SCD, which is caused by a single amino acid substitution (Glu to Val) in the sixth position of the HBB gene (Dever et al., 2016; DeWitt et al., 2016; Park et al., 2019; Pattabhi et al., 2019; Romero et al., 2019), and for X-linked chronic granulomatous disease (CGD), often caused by mutations in the CYBB gene (De Ravin et al., 2017, 2021); (ii)in situ gene correction by targeted insertion of a cDNA: many monogenetic diseases are not caused by a recurrent single nucleotide mutation, but rather different mutations affecting the same gene. Here, HBB is linked to Schnyder corneal dystrophy.