CD34+ HSPCs from three HBBS/S patients with SCD were electroporated with ABE8e-NRCH RNP using an sgRNA targeting the SCD mutant codon, followed by transplantation of 2–5 × 105 treated cells into NBSGW mice via tail-vein injection. Mice were euthanized and analysed 16 weeks after transplantation. a, Experimental workflow. b, Engraftment measured by the percentage of human donor CD45+ cells (hCD45+ cells) in recipient mouse bone marrow. c, Human B cells (hCD19+), myeloid cells (hCD33+), and T cells (hCD3+) in recipient mouse bone marrow, shown as percentages of the total hCD45+ population. d, Human erythroid precursors (hCD235a+) in recipient mouse bone marrow, shown as a percentage of total human and mouse CD45–cells. e, On-target (A7, Fig. 1a) editing efficiencies in human donor CD34+ cell-derived lineages purified from recipient bone marrow by FACS. Erythroid, myeloid, B cell, and HSPC human lineages were collected using antibodies against hCD235a, hCD33, hCD19, and hCD34, respectively. Statistical significance was assessed by one-way ANOVA to compare groups; ns, not significant. f, Percentages of β-like globin proteins determined by reverse-phase HPLC analysis of human donor-derived reticulocytes isolated from recipient mouse bone marrow. g, Representative phase contrast images of human reticulocytes purified from bone marrow and incubated for 8 h with 2% oxygen. Nine images of more than 50 cells per image were collected per sample. Scale bars, 50 μm. h, Quantification of sickled cells calculated by counting images after incubation for 8 h in 2% oxygen as in g. More than 300 randomly selected cells per sample were counted by a blinded observer. n = 14 total mice analysed (b–f); triangle, square, and circle symbols represent samples from three different donors with SCD. Negative control data are shared with Fig. 2. Data shown as mean ± s.d. Statistical significance between treated and untreated samples was assessed using two-tailed Student’s t-test.