Upon transplantation of manipulated HSPCs into immunodeficient mice, 15–20% of corrected cells persisted in transplanted animals for up to 5 months, with restored physiological expression of the gp91phox in mature phagocytes and proper functionality of the NADPH oxidase.24 Despite these encouraging data, whether such gene correction is sufficient to alleviate the pathogenesis of CGD remains to be investigated, as corrected X-CGD cells do not have a selective advantage in vivo. The gene discussed is CYBB; the disease is chronic granulomatous disease.