In vivo, the xenotransplantation of lentivirally transduced human ALD CD34+ cells into non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice demonstrated that these human genetically modified hematopoietic cells were able to migrate into the brain of transplanted mice and to differentiate into microglia-like cells expressing the human ALD protein [10, 17]. Here, CD34 is linked to X-linked adrenoleukodystrophy.