1 Down Syndrome Program, Division of Medical Genetics and Metabolism, Department of Pediatrics, Massachusetts General Hospital, Boston, Massachusetts, USA.
2 Department of Pediatrics, Harvard Medical School, Boston, Massachusetts, USA.
3 Department of Neurology, Harvard Medical School, Boston, Massachusetts, USA.
4 Boston Children's Hospital Down Syndrome Program, Boston Children's Hospital, Boston, Massachusetts, USA.
5 Geisinger Health System, Danville, Pennsylvania, USA.
6 Mater Research Institute-University of Queensland, The University of Queensland, South Brisbane, Australia.
7 Department of Pediatrics, Duke University Medical Center, Durham, North Carolina, USA.
8 Biostatistics Center, Massachusetts General Hospital, Boston, Massachusetts, USA.
9 Down Syndrome Center of Western Pennsylvania, UPMC Children's Hospital of Pittsburgh, Pittsburgh, Pennsylvania, USA.
10 Pediatric and Infectious Disease Unit, Bambino Gesù Children's Hospital, Rome, Italy.