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About Sickkids
About SickKids

Walter Kahr, MD, PhD, FRCPC

The Hospital for Sick Children
Staff Physician

Research Institute
Senior Scientist
Cell Biology

University of Toronto
Departments of Paediatrics and Biochemistry

Phone: 416-813-7977
Fax: 416-813-5327
Email: walter.kahr@sickkids.ca
Alternate Contact: Eleanor Paulino
Alternate Phone: 416-813-7654 ext. 205886
Alternate Email: eleanor.paulino@sickkids.ca

For more information, visit:

The Kahr Lab 

Brief Biography

Dr. Kahr received his MD and PhD (Biochemistry) from the University of Toronto in 1994. After post-graduate training in Internal Medicine (University of Toronto), Hematology (McMaster University), and a post-doctoral fellowship in the Department of Pathology and Molecular Medicine (McMaster University), he joined the Division of Haematology/Oncology at SickKids in 2003 as a Clinician-Scientist. He is currently a Senior Scientist in the Cell Biology Program of the Research Institute with a research laboratory at the Peter Gilgan Centre for Research and Learning. His main research interests are haemostasis and thrombosis, with a focus on the role of platelets in health and disease.

Clinical Activities

  • Staff physician in the Division of Haematology/ Oncology at SickKids
  • Staff consultant to the Department of Paediatric Laboratory Medicine at SickKids
  • Co-Director of the of the Clinical Haemostasis Research Laboratory at SickKids
  • Application of advanced haemostatic assays and cell/molecular biology analysis for diagnosis and treatment of paediatric patients with bleeding/clotting disorders and other issues (e.g. ventricular assist devices).
  • Care of paediatric patients with abnormal bleeding and clotting disorders
  • Clinical Director of the Association of Hemophilia Clinical Directors of Canada (AHCDC)
  • Member of the Rare Inherited Bleeding Disorder Subcommittee of the AHCDC
  • Member of the Canadian Pediatric Thrombosis and Hemostasis Network (CPTHN)
  • Member of the Executive Committee, US National Institutes of Health ClinGen Rare Gene Variant Curation Group, Hemostasis/Thrombosis Clinical Domain Working Group
  • Member, US National Institutes of Health ClinGen Platelet Function Disorder Subgroup

Research Interests

  • Inherited bleeding/clotting disorders (e.g. hemophilia, sickle cell disorder, platelet defects)
  • Platelet development and function
  • Cell biology of platelet secretory granule development, with focus on alpha granule biogenesis and the roles of VPS16B, VPS33B, NBEAL2 and other proteins
  • Cell biology of platelet precursor megakaryocytes
  • Identification of genetic basis of currently undiagnosed platelet and bleeding disorders

Platelets coordinate blood clotting at wound sites, and they also transport and secrete a wide assortment of proteins and small molecules. Deficiencies in these platelet functions are associated with bleeding disorders, and platelets are also intimately involved in the formation of arterial plaques, and the thrombi that cause heart attacks and strokes, both major causes of mortality. 

Research in my laboratory is aimed at understanding the roles of platelets in health and disease. Key insights into platelet development and function have come from studies of inherited platelet disorders. For example research into the severe multisystem disorder ARC syndrome led to our identification of VPS16B and VPS33B as proteins that are essential for the production of secretory alpha granules by platelet precursor megakaryocytes, and studies of gray platelet syndrome led to the identification another key protein, NBEAL2. In a recent collaborative study we identified ARPC1B deficiency in a patient at SickKids. This condition has profound consequences for platelet production and function, immunity, inflammation and other aspects of physiology.

For an overview of recent research highlights, visit The Kahr Lab website.

External Funding

Our research is primarily funded by project grants from the Canadian Institutes of Health Research, and trainee awards from the National Sciences and Engineering Research Council of Canada, and Restracomp. We have also received competitive funding from the Heart and Stroke Foundations of Ontario and Canada, the Canadian Hemophilia Society, and the Bayer-Canadian Blood Services - Hema Quebec Partnership Fund.


For a complete listing of Dr. Kahr's papers visit Pub Med.