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  • Main Hospital

    Washington, District of Columbia 20010
    1-888-884-BEAR (2327)

Education & Training

  • Fellowship Program, Genetics, 1990
    Vanderbilt University
  • Residency Program, Pediatrics, 1988
    Vanderbilt University
  • Internship Program, Pediatrics, 1986
    Vanderbilt University
  • MD, 1985
    University of Tennessee College of Medicine
  • BS, 1981
    Vanderbilt University

Board Certifications

  • American Board of Med. Genetics/Clinical Genetics
  • American Brd of Med Genetics/Clin Biochemical Gen

National Provider ID: 1336231745


Marshall Summar, M.D., is well-known for his pioneering work in caring for children diagnosed with rare diseases. He joined Children’s National in 2010 from Vanderbilt University. At Children’s National he leads the Division of Genetics and Metabolism, currently the largest clinical division in the world seeing over 8,500 patients a year with rare diseases. Dr. Summar’s laboratory works on both devices and treatments for patients with genetic diseases and adapting knowledge from rare diseases to mainstream medicine. His work has resulted in new drugs in FDA trials for patients with congenital heart disease and premature birth. He has over 30 patents and patent applications. His laboratory is best known for its work in the rare diseases affecting nitrogen and ammonia metabolism. 

Dr. Summar has also organized and led a large number of international work groups to develop standards of care and treatment for rare diseases resulting in significant improvements in outcomes. Dr. Summar developed a program with NIH where very young children can benefit from NIH research programs at Children’s National. Dr. Summar is board-certified in Pediatrics, Clinical Genetics and Biochemical Genetics and has been listed with Best Doctor’s in America since 2004. He serves on the board of directors of the National Organization for Rare Disorders (Chairman) and the Society of Inherited Metabolic Diseases (President). He directs the National Organization for Rare Diseases Scientific and Medical Advisory Committee and is spearheading an effort to develop national standards for families to collect information about poorly understood rare diseases affecting 25 million Americans. Dr. Summar also holds the Margaret O'Malley Professorship in Genetic Medicine. He is very active in newborn screening issues, developing testing and follow-up systems.

This faculty member (or a member of their immediate family) has a working relationship (i.e. consulting, research, and/or educational services) with the companies listed below. These relations have been reported to the health system leadership and, when appropriate, management plans are in place to address potential conflicts.

Outside Interests

  • Asklepion Pharmaceuticals

Assessing the functional characteristics of synonymous and nonsynonymous mutation candidates by use of large DNA constructs

(2007) Am. J. Hum. Genet

Current strategies for the management of neonatal urea cycle disorders

(2001) J. Pediatr

Diagnosis symptoms frequency and mortality of 260 patients with urea cycle disorders from a 21year multicentre study of acute hyperammonaemic episodes

(2008) Acta Paediatr

DLCitrulline ameliorates chronic hypoxia-induced pulmonary hypertension in newborn piglets

(2009) Am. J. Physiol Lung Cell Mol. Physiol

Genetic continuity after the collapse of the Wari empire Mitochondrial DNA profiles from Wari and postWari populations in the ancient Andes

(2009) Am. J. Phys. Anthropo

Genetic variation in the urea cycle a model resource for investigating key candidate genes for common diseases

(2009) Hum. Mutat

Neonatal pulmonary hypertension urea cycle intermediates nitric oxide production and carbamoylphosphate synthetase function

(2001) N. Engl. J. Med

Nitric oxide precursors and congenital heart surgery a randomized controlled trial of oral citrulline

(2006) J. Thorac. Cardiovasc. Surg

Pharmacokinetics and safety of intravenously administered citrulline in children undergoing congenital heart surgery potential therapy for postoperative pulmonary hypertension

(2007) J. Thorac. Cardiovasc. Surg