CD34 and Schnyder corneal dystrophy: Drawing on pairs of CRISPR/Cas nucleases, Ye et al. induced a 12.9-kb deletion in the HBB locus that left the HBG1/2 genes intact but largely removed HBD and HBB, which led to reversal of the SCD phenotype and an increase in HbF levels in SCD CD34+ HSCs [145].