1 Division of Hematology/Oncology and Department of Radiology, Boston Children's Hospital, Boston, Massachusetts.
2 Advanced Magnetic Resonance Imaging Center, Department of Radiology, University of Massachusetts Medical School, Worcester.
3 Unit of Rare Neurodegenerative and Neurometabolic Diseases, Fondazione Instituto di Ricovero e Cura a Carattere Scientifico, Istituto Neurologico "C. Besta," Milan, Italy.
4 Gene Therapy Program, Dana Farber/Boston Children's Cancer and Blood Disorders Center, Boston, Massachusetts.
5 Gene Therapy Program for Rare Diseases, Boston Children's Hospital, Boston, Massachusetts.