基因添加技术已被用来治疗一些遗传病，但毒性仍是一大问题。这使得基因修复(仅以缺陷基因为目标)成为一个有吸引力的替代方案。Luigi Naldini 及同事在本文中报告了在人类造血干细胞(HSCs)中成功进行的定向基因组编辑。他们通过量身定制输送平台和培养条件克服了以前所存在的障碍。这种方法的治疗潜力通过向来自健康供者和一位“与X-相关的严重复合免疫缺陷症”(SCID-X1)患者的HSCs的IL2RG基因的一个突变热点中插入一个纠正性cDNA得到了演示。通过基因编辑的HSCs产生功能性淋巴样细胞，后者相对于那些携带破坏性IL2RG突变的淋巴样细胞具有一个选择性生长优势。
Targeted genome editing by artificial nucleases has brought the goal of site-specific transgene integration and gene correction within the reach of gene therapy. However, its application to long-term repopulating haematopoietic stem cells (HSCs) has remained elusive. Here we show that poor permissiveness to gene transfer and limited proficiency of the homology-directed DNA repair pathway constrain gene targeting in human HSCs. By tailoring delivery platforms and culture conditions we overcame these barriers and provide stringent evidence of targeted integration in human HSCs by long-term multilineage repopulation of transplanted mice. We demonstrate the therapeutic potential of our strategy by targeting a corrective complementary DNA into the IL2RG gene of HSCs from healthy donors and a subject with X-linked severe combined immunodeficiency (SCID-X1). Gene-edited HSCs sustained normal haematopoiesis and gave rise to functional lymphoid cells that possess a selective growth advantage over those carrying disruptive IL2RG mutations. These results open up new avenues for treating SCID-X1 and other diseases.