(2) Gene therapy for SCD is achieved by interfering with the expression and function of the HBG1/HBG2 transcriptional repressor BCL11 transcription factor A (BCL11A) or zinc finger and BTB structural domain‐containing 7A (ZBTB7A) or by inducing the hereditary persistence of HbF (HPFH), which raises the level of HbF.218, 219. Here, HBG1 is linked to Schnyder corneal dystrophy.