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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 Pediatrics
  • American Brd of Med Genetics/Clin Biochemical Gen
  • American Board of Medical Genetics and Genomics

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 Hospital in 2010 from Vanderbilt University and holds board certifications in both pediatrics and clinical genetics and biochemical genetics. He has been listed with Best Doctors in America since 2004.

At Children’s National, Dr. Summar leads the Division of Genetics and Metabolism, currently the largest clinical division in the world seeing over 8,000 patients a year with rare diseases. Dr. Summar’s laboratory works on both devices and treatments for patients with genetic diseases, while transferring knowledge from rare diseases to support advancements in mainstream medicine. His work has resulted in new drugs in FDA trials for patients with congenital heart disease and premature birth.

Dr. Summar holds more than 60 patents and patent applications, has published more than 140 peer-reviewed research studies and has guided more than 25-funded research projects, with support from the National Institutes of Health (NIH), industry and independent philanthropists. 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.   

In addition to guiding clinical research and treatment, Dr. Summar developed and launched the world’s first Rare Disease Institute (RDI) at Children’s. This RDI focuses on developing the clinical care field of more than 7,000 rare diseases currently recognized. The RDI is the first Clinical Center of Excellence designated by the National Organization for Rare Diseases (NORD) and focuses on building best clinical practices and diagnostic pathways for patients.

Dr. Summar is part of the Global Commission to reduce the time to diagnosis for rare disease and is partnering with Microsoft to develop an undiagnosed patient registry program with NORD. With NORD and the FDA, Dr. Summar has worked to develop a patient-driven natural history platform employed by over 35 rare disease advocacy organizations.

Dr. Summar is the current Board of Directors Chairman for NORD, the past president for the Society for Inherited Metabolic Disorders and serves on a number of rare-disease related advisory groups.

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

Research & Publications

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