1. From the Department of Neurology, Children’s Hospital Los Angeles, CA (J.D.S.)
2. Department of Neurology, Keck School of Medicine, University of Southern California, Los Angeles (J.D.S.)
3. Department of Neurology, Massachusetts General Hospital, Boston (J.D.S.)
4. Harvard Medical School, Boston, MA (J.D.S., B.G.S.)
5. Division of Child Neurology, Stanford University, Palo Alto, CA (S.L., M.M., E.W.M.)
6. Alzheimer’s Therapeutic Research Institute (ATRI), Keck School of Medicine, University of Southern California, San Diego (M.S.R.)
7. Down Syndrome Program, Division of Medical Genetics, Department of Pediatrics, Massachusetts General Hospital, Boston (B.G.S.).