Highly efficient correction of engrafting X-CGD HSPCs by SpCas9/sg mRNA/ODN donor with i53. (A) Peripheral blood (PB) from mice transplanted with X-CGD HSPCs GE with ODN or AAV (CYBB E7-13pA) analyzed at weeks 8, 12, and 26 for engraftment (hCD45⁺). (B) Percentages of gp91^phox+ cells in hCD45⁺ PB. (C) FACS showing human CD45⁺ engraftment in mice bone marrow (BM) 18 to 26 weeks after transplant with ODN mutation-repaired X-CGD HSPCs (n = 3 patients). (D) Gp91^phox expression in myeloid-differentiated BM human CD45⁺ cells from NSG transplanted with ODN mutation–repaired X-CGD HSPCs (3 patients). (E) DHR assay showing ROS production in the myeloid-differentiated cells in panel D. (F) Lineage (CD33⁺ and CD19⁺) composition in BM, PB, and spleen of transplanted mice. (G) Gp91^phox expression in CD33⁺ myeloid cells in myeloid-differentiated BM and PB. (H) Percentages of gp91^phox+ before (in vitro) and after transplant (BM) with ODN-treated cells using Cas9 RNA (±i53) vs RNP (n = 4 experiments; 3 X-CGD patients, 11 mice). (I) Correction rates (% corrected alleles) before (input, 5 days post-electroporation, blue) vs after transplant (red) (n = 3 X-CGD patients). **P < .001.