Lead Sponsor: Mendel Tuchman

Collaborators: Children's Hospital of Philadelphia, University of California, Los Angeles, Boston Children's Hospital, University of Colorado, Denver, University Hospitals Cleveland Medical Center, Children's National Research Institute, Lucile Packard Children's Hospital

Intervention / Treatment: OTHER: Standard of Care, DRUG: N-carbamylglutamate

Lead Sponsor: Mendel Tuchman

Collaborators: Children's Hospital of Philadelphia, University of California, Los Angeles, Stanford University, University of Pittsburgh, Boston Children's Hospital, University Hospitals Cleveland Medical Center, Children's National Research Institute, Children's Hospital Colorado, Icahn School of Medicine at Mount Sinai

Intervention / Treatment: DRUG: Placebo, DRUG: Carbaglu

Lead Sponsor: Mark Batshaw

Collaborators: Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD), Rare Diseases Clinical Research Network