Unlike HA, HB is caused primarily by point mutations in F9 and could be corrected in iPSC models using mutation-specific CRISPR-Cas9-mediated HDR, in addition to more universal approaches, such as CRISPR-Cas9-mediated insertion of a F9 cDNA into exon 1 of the mutant gene or into the AAVS1 safe harbor locus (Lyu et al., 2018; Ramaswamy et al., 2018). The gene discussed is F9; the disease is hemoglobin measurement.