James T Bennett, MD, PhD

James T Bennett, MD, PhD

Genetics, Laboratory Medicine

On staff since August 2012

Children's Title: Attending Physician

Academic Title: Associate Professor, Department of Pediatrics, University of Washington School of Medicine

Research Center: Center for Developmental Biology and Regenerative Medicine

"Applying novel diagnostic approaches for specific genetic diagnosis in children with vascular anomalies and mosaic disorders "

  • James Bennett, MDPhD, is an associate professor in the Department of Pediatrics, Division Genetic Medicine, and and adjunct associate professoer in the Department of Lab Medicine and Pathology. His clinical and research focus is on vascular anomalies and other genetic disorders caused by post-zygotic mosaicism.

    • Jason Olympia 01.07.15

      Truely excellent. My wife and I wish he could be our daughters full time doctor. Treats you like family and puts forward 100% effort.

  • Award Name Award Description Awarded By Award Date
    CSHL Advanced Sequencing Course Participant 2015
    Burroughs Wellcome Career Award Recipient 2015
  • Other Publications

    • Bennett JT, Tan TY, Alcantara D, Tétrault M, Timms AE, Jensen D, Collins S, Nowaczyk MJ, Lindhurst MJ, Christensen KM, Braddock SR, Brandling-Bennett H, Hennekam RC, Chung B, Lehman A, Su J, Ng S, Amor DJ, University of Washington Center for Mendelian Genomics, Care4Rare Canada Consortium, Majewski J, Biesecker LG, Boycott KM, Dobyns WB, O'Driscoll M, Moog U, McDonell LM
      Mosaic Activating Mutations in FGFR1 Cause Encephalocraniocutaneous Lipomatosis.
      26942290 American journal of human genetics, 2016 Mar 3 : 98(3)579-87
    • Luks VL, Kamitaki N, Vivero MP, Uller W, Rab R, Bovée JV, Rialon KL, Guevara CJ, Alomari AI, Greene AK, Fishman SJ, Kozakewich HP, Maclellan RA, Mulliken JB, Rahbar R, Spencer SA, Trenor CC 3rd, Upton J, Zurakowski D, Perkins JA, Kirsh A, Bennett JT, Dobyns WB, Kurek KC, Warman ML, McCarroll SA, Murillo R
      Lymphatic and other vascular malformative/overgrowth disorders are caused by somatic mutations in PIK3CA.
      25681199 The Journal of pediatrics, 2015 April : 166(4)1048-54.e1-5 PMCID:PMC4498659
    • Kunwar PS, Zimmerman S, Bennett JT, Chen Y, Whitman M, Schier AF
      Mixer/Bon and FoxH1/Sur have overlapping and divergent roles in Nodal signaling and mesendoderm induction.
      14522874 Development (Cambridge, England), 2003 Dec. : 130(23)5589-99
  • Presentations Title Event Location Date
    Molecular Testing: Where We Started, Where We Are Now, What Does the Future Hold? American Society for Clinical Laboratory Science 2016 Meeting Seattle, WA Apr 16, 2016
    Mosaic Activating Mutations in FGFR1 Cause Encephalocraniocutaneous Lipomatosis 17th Seattle Developmental Biology Winter Symposium Seattle, WA Dec 5, 2015
    Mosaicism, a New Frontier in Pediatric Genetics: How Many Mutations Are We Missing By Only Testing Our Patient's Blood? Department of Pediatrics Grand Rounds presentation Seattle, WA Jul 23, 2015
    Genetic Testing Dilemmas Addressed by Leading Experts Happy Lab, Happy Life Lab Talk Series Seattle, WA Jul 21, 2015
    Impact of Somatic Mutations on Birth Defects Department of Genetic Medicine Retreat Seattle, WA Feb 4, 2014
    Whole Exome Sequencing Identifies de Novo Mutations in GATA6 Associated with Congenital Diaphragmatic Hernia New Orleans Children's Hospital Dept. of Genetics New Orleans, LA Oct 18, 2013
    Exome sequencing and MIPS identify GATA6 as a novel gene responsible for congenital diaphragmatic hernia Northwest Genetics Exchange Vancouver, BC May 3, 2013
    GATA6, new candidate gene for congenital diaphragmatic hernia, a common birth defect Department of Genetic Medicine Retreat Seattle, WA Feb 26, 2013
    Autosomal Dominant Presentation of Wilson Disease Inborn Errors of Metabolism conference Seattle, WA Oct 5, 2011
    A case of neonatal hepatosplenomegaly Northwest Genetics Exchange Vancouver, BC May 6, 2011
  • Grant Title Grantor Amount Award Date
    Mosaicism in Human Tissues, from Telomere to Telomere NIH/NIDA 12,500,00 May 1, 2023 - Apr 30, 2028
    Utilization of Advanced Technologies for the Understanding of Human Structural Birth Defects NIH/NICHD 3,800,000 Dec 1, 2020 - Nov 30, 2025
    Mosaic: post-zygotic mutations in vascular malformations NIH/NHLBI 2,500,000 Sep 1, 2020 - Jun 30, 2025
    Burroughs Wellcome Career Award for Medical Scientists $700,000 2016
    Pediatric Early Research Career (PERC) award Seattle Children's Research Institute $177,000 2015 - 2016


Board Certification(s)

Medical Genetics, Clinical Molecular Genetics
Medical Genetics, Clinical Genetics (M.D.)

Medical/Professional School

New York University School of Medicine, New York, NY


University of Washington, Seattle, WA

Clinical Interests

Vascular anomalies

Mosaic Disorders

Application of Genetic Testing to rare pediatric diseases

Research Description

Almost all genetic sequencing is performed from blood or saliva derived DNA, which implicitly assumes that the genomes of blood cells are the same as every other cell in the body. Because errors occur in DNA replication with every division, all individuals carry genetic variants that are not present in every cell in the body. This has major implications for diagnosis of children with genetic disorders, since pathogenic mutations that are absent, or present at low levels in the blood will not be detected by current standard methods.

To address this, the Bennett lab develops methods for accurate detection of these "hidden" low-level mosaic variants, with a major focus on vascular anomalies. We are also interested in measuring the "normal" rate and distribution of somatic variation in individuals across their lifespan.

Research Focus Area

vascular anomalies, Somatic Mosaicism