1 Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
2 Biostatistics and Research Design Center, Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts.
3 Guy's and St. Thomas' NHS Foundation Trust, London, UK.
4 Oxford University Hospitals NHS Foundation Trust, Oxford, UK.
5 Department of Neurology, Universitäts-Kinderspital beider Basel, Basel, Switzerland.
6 Hôpitaux Universitaires Paris Sud-Bicêtre, Paris, France.
7 Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania; Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
8 Division of Neurology, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania.
9 Division of Hematology, Oncology, and Stem Cell Transplantation, Ann & Robert H. Lurie Children's Hospital of Chicago, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
10 Division of Neurology, Children's Hospital Los Angeles, Keck School of Medicine of University of Southern California, Los Angeles, California.
11 Department of Pediatrics, Memorial Sloan Kettering Cancer Center, New York, New York; Department of Pediatrics, Weill Cornell Medical College, New York, New York.
12 Department of Neurology, Texas Children's Hospital, Houston, Texas.
13 Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; Biostatistics and Research Design Center, Institutional Centers for Clinical and Translational Research, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: bo.zhang@childrens.harvard.edu.
14 Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts. Electronic address: mark.gorman@childrens.harvard.edu.