ADA and chronic granulomatous disease: Although the protocols were comparable in terms of gene delivery, culture and transduction conditions, gene-modified cells of CGD patients are not known to have survival and proliferative advantages over non-transduced cells, as is the case in SCID-X1 and ADA-SCID, imposing the necessity of (partial) myeloablation previous to the reinfusion of gene modified cells for CGD.