Baylor College of Medicine, Houston, TX, USA. Electronic address: blee@bcm.edu. Icahn School of Medicine at Mount Sinai, New York, NY, USA. The Medical College of Wisconsin, Milwaukee, WI, USA. Drexel University College of Medicine, Philadelphia, PA, USA. Univ. of CA, San Diego, CA, USA. Univ. of Minnesota, Minneapolis, MN, USA. National Urea Cycle Disorders Foundation, Pasadena, CA, USA. Miller Children's Hospital, Long Beach, CA, USA. Univ. of UT, Salt Lake City, UT, USA. Baylor College of Medicine, Houston, TX, USA. Stanford Univ., Palo Alto, CA, USA. Univ. of CA, San Francisco, USA. Oregon Health Sciences, Portland, OR, USA. Case Western Reserve Univ. Medical Center, Cleveland, OH, USA. Maine Medical Ctr., Portland, ME, USA. The Hospital for Sick Children, Univ. of Toronto, Canada. MED Technical Consulting, Inc., Union City, CA, USA. Horizon Therapeutics, Brisbane, CA, USA.