1 Department of Neurology, Saint Louis University School of Medicine, St. Louis, Missouri 63110-0250, USADepartment of Molecular Microbiology and Immunology, Saint Louis University School of Medicine, St. Louis, Missouri 63110-0250, USAInstitute for Molecular Virology, Saint Louis University School of Medicine, St. Louis, Missouri 63110-0250, USASt. Louis Veterans Administration Hospital, Saint Louis University School of Medicine, St. Louis, Missouri 63110-0250, USACardinal Glennon Hospital, Saint Louis University School of Medicine, St. Louis, Missouri 63110-0250, USADepartment of Neurology, University of Western Ontario, London, Ontario N6A 5A5, CanadaDepartment of Neurology, West Virginia University Health Sciences Center, Morgantown, West Virginia 26506-9180, USACenter for Human Genetics, Boston University, Boston, Massachusetts 02118-2394, USADepartment of Pathology, Boston University, Boston, Massachusetts 02118-2394, USADepartment of Pediatrics, Boston University, Boston, Massachusetts 02118-2394, USA.