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Sevan Hopyan

Title: Orthopaedic Surgeon, Division of Orthopaedics
Designations: MD, PhD, FRCSC
Phone: 416-813-7654 ext. 202045
Alternate Contact Name: Bonnie Louie
Alternate Phone: 416-813-2045
Alternate Email:
U of T Positions: Associate Professor, Department of Molecular Genetics and Department of Surgery

Research Positions

Senior Scientist
Developmental and Cell Biology


Sevan Hopyan is an orthopaedic surgeon specialising in paediatric musculoskeletal tumours and upper extremity reconstruction. His laboratory focuses on developmental biology, and mechanisms of morphogenesis of organ primordial in particular.


Sevan Hopyan’s laboratory asks how organs form in the embryo. They focus on physical and genetic mechanisms that transform groups of cells into tissues such as the developing limbs, face and other organs. These investigations will help us to better understand how congenital anomalies arise and contribute to regenerative approaches. Dr. Hopyan’s clinical research focuses on outcomes of surgery for sarcoma and upper limb reconstruction for sequelae of brachial plexus birth palsy.

Education and experience

  • January 2004–June 2004: Clinical Fellow, Orthopaedic Oncology, St. Vincent’s Hospital, Melbourne, Australia
  • July 2003–December 2003: Clinical Fellow, Paediatric Orthopaedic Surgery, Royal Children’s Hospital, Melbourne, Australia
  • 1995–1997, 2001–2003: Postgraduate Trainee, Division of Orthopaedic Surgery, Department of Surgery, University of Toronto
  • 1997–2001: Doctor of Philosophy, Institute of Medical Science, University of Toronto
  • 1991–1995: Doctor of Medicine, University of Toronto

Clinical experience

  • January 2005–December 2014: Assistant (2005-2014), Associate (2015-) Professor Department of Surgery, University of Toronto
  • January 2005–Present: Paediatric Orthopaedic Surgeon, The Hospital for Sick Children, Toronto
  • July 2004–December 2004: Locum Consultant Paediatric Orthopaedic Surgeon, Royal Children’s Hospital and Sunshine Hospital, Melbourne, Australia

Research experience

  • July 2012–Present: Assistant (2012-2014), Associate (2015-) Professor, Department of Molecular Genetics, University of Toronto
  • September 2008–Present: Scientist (2008-2014), Senior Scientist (2015-), Program in Developmental and Stem Cell Biology, Research Institute, The Hospital for Sick Children, Toronto
  • January 2005–September 2008: Scientist-Track Investigator, Program in Developmental and Stem Cell Biology, Research Institute,
 The Hospital for Sick Children, Toronto


  1. Tao H, Lambert J-P, Li D, Lau K, Hahn NA, Sturgeon K, Puviindran V, Zhang X, Chen XX, Anderson G, Gong W, Garry DJ, Henkelman RM, Kawakami Y, Gingras A-C, Hui C-c, Hopyan S. IRX3 and IRX5 regulate mitotic chromatid segregation and limb bud shape in a nontranscriptional manner. Development, in press.
  2. Zhu M, Tao H, Samani M, Luo M, Wang X, Hopyan S, Sun Y. Spatial mapping of tissue properties in vivo reveals a 3D stiffness gradient in the mouse limb bud. Proceedings of the National Academy of Sciences of the Unitited States of America, 117(9):4781-4791. doi: 10.1073/pnas.1912656117 (2020); preprint: bioRxiv 412072.
  3. Tao H, Zhu M, Lau K, Whitley OKW, Samani M, Xiao X, Chen XX, Hahn NA, Liu WL, Valencia M, Wu M, Wang X, Fenelon KD, Pasiliao CC, Hu D, Spring, Ferguson J, Karuna E, Henkelman RM, Dunn A, Ho H-YH, Atit R, Goyal S, Sun Y, Hopyan S. Oscillatory cortical forces promote three dimensional mesenchymal cell intercalations that shape the mandibular branchial arch. Nature Communications 10, 1703, 1-18. doi: 10.1038/s41467-019-09540-z (2019); preprint: bioRxiv 309120.
  4. Piscione J, Barden W, Malkin A, Roy T, Barry J, Naqvi M, Fitzgerald C, Mazil K, Salomon S, Griffin A, Saint-Yves H, Sargeant J, Sueyoshi T, Giuliano P, Gupta A, Ferguson P, Scheinemann K, Ghert M, Turcotte RE, Lafay-Cousin L, Werier J, Strahlendorf C, Isler M, Mottard S, Afzal S, Anderson ME, Hopyan S. Pediatric Toronto Extremity Salvage Score (pTESS): Validation of self-reported measure functional outcomes tool for children with extremity tumors. Clinical Orthopaedics and Related Research, 477(9):2127-2141.
  5. Lau K, Tao H, Liu H, Wen J, Sturgeon K, Sorfazlian N, Lazic S, Burrows JTA, Wong MD, Li D, Deimling S, Ciruna B, Scott I, Simmons C, Henkelman RM, Williams T, Hadjantonakis K, Fernandez-Gonzalez R, Sun Y, Hopyan S. Anisotropic stress orients remodelling of mammalian limb bud ectoderm. Nature Cell Biology, 17(5):569-79 (2015).

See a full list of Sevan Hopyan's publications

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