This trial will assess the efficacy and safety of autologous CD34+ hematopoietic stem cells, transduced ex-vivo with Lenti-D lentiviral vector, for the treatment of childhood cerebral adrenoleukodystrophy (CCALD). A subject’s blood stem cells will be collected and modified using the Lenti-D lentiviral vector to add a functional copy of the human ABCD1 (ATP-binding cassette, sub-family D, member 1) complementary DNA (cDNA). After modification with the Lenti-D lentiviral vector, the cells will be transplanted back into the subject following myeloablative conditioning. [gene transfer; ALD]