CD34+ HSPCs were thawed and cultured in StemSpan ACF (StemCell Technologies) supplemented with 100 ng/ml SCF (Feldan), 100 ng/ml FLT3-l (Peprotech), 50 ng/ml TPO (StemCell Technologies), 10 µg/ml LDL (StemCell Technologies), and 35 nM UM171 (StemCell Technologies) for 16–24 h after thawing. Cells were then nucleofected with Cas9 RNP and ssODNs with an Amaxa 4D Nucleofector X unit (Lonza) and the E0-100 program, according to the manufacturer’s recommendations. K562, HEK293LTV, RPE-1:Cells (2 × 105 per transfection) were transfected with an Amaxa 4D-Nucleofector (Lonza), per the manufacturer’s recommendations.