Extended Data Figure 10: IL2RG gene correction in CD34⁺ cells from the bone marrow of a genotyped subject with SCID-X1.

a, Blood cell counts in the peripheral blood and bone marrow of a SCID-X1 male child carrying the R289X mutation in the IL2RG gene (see Supplementary Information) and showing virtual absence of T and NK cells. Asterisks in the left-most table indicate values calculated within the leukocyte gate. b, Left: representative density plots showing the cellular composition of a bone marrow harvest from a healthy donor (top) and the subject with SCID-X1 (bottom) after purification of nucleated cells (bone-marrow-derived mononuclear cells, BMMCs). Myeloid cells are stained for CD15 and CD33, B cells for CD19, T cells for CD3 and NK cells for CD16. Right: γ-chain expression within the indicated cell populations gated from the plots shown on the left. As expected from the missense R289X mutation, the γ-chain protein is expressed on the cell surface but it is not functional, as indicated by the absence of T and NK cells in the patient. In Fig. 5 we show normal expression of the γ-chain protein in the myeloid cell progeny of three gene-corrected CFCs from the patient cells (gene correction was proven by evidence of targeted integration in the only IL2RG allele of this male individual in the clonal CFC progeny and by the expression of the fusion transcript bearing the corrective cDNA). These data indicate normal γ-chain expression from the reconstituted allele in the edited patient cells. c, Bright-field and fluorescence microscopy images of the three GFP⁺ myeloid colonies obtained after IL2RG gene correction of SCID-X1 cells.