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About Sickkids
About SickKids

Sevan Hopyan, MD, PhD, FRCSC

The Hospital for Sick Children
Orthopaedic Surgeon
Orthopaedic Surgery

Research Institute
Senior Scientist
Developmental & Stem Cell Biology

University of Toronto
Associate Professor
Department of Surgery

Associate Professor
Department of Molecular Genetics

Phone: 416-813-7654 ext. 202045
Fax: 416-813-6414
Email: sevan.hopyan@sickkids.ca

For more information, visit:

Lab website

Brief Biography


Dr. Hopyan’s clinical work focuses on paediatric orthopaedic oncology.  He undertakes surgical resections and biological and endoprosthetic limb reconstructions using the best available methods that are specifically appropriate for children with primary bone and soft tissue tumours.  Another area of focus is upper extremity reconstruction to address the sequelae of brachial plexus birth palsy.  Dr. Hopyan developed a method of surgically correcting severe shoulder deformity in this population.  Both of these fields involve multidisciplinary clinics and team approaches.  Congenital limb anomalies and other paediatric orthopaedic conditions requiring complex reconstruction are also areas of clinical interest.  Dr. Hopyan’s multidisciplinary clinical team is generating a paediatric- and sarcoma-specific outcome measure to compare the function of various limb salvage and reconstruction approaches.

Dr. Hopyan’s orthopaedic residency training was undertaken at the University of Toronto.  His orthopaedic oncology fellowship training took place at St. Vincent’s Hospital and the Peter MacCallum Cancer Centre in Melbourne, Australia, while his paediatric orthopaedic fellowship and limb reconstruction training was at The Royal Children’s Hospital, also in Melbourne, where he was later a locum consultant paediatric orthopaedic surgeon prior to returning to Toronto.  


Dr. Hopyan is a scientist in the Developmental & Stem Cell Biology Program within the SickKids Research Institute.  His PhD work focused on how developmental signalling pathways that regulate growth plate chondrocyte differentiation are deranged in cartilaginous neoplasia.  He identified and characterised the first known mutation that causes enchondromatosis.  That basic work subsequently lead to a clinical drug trial aimed at improving outcomes for patients with advanced chondrosarcoma.

Dr. Hopyan’s current area of interest is vertebrate limb development.  His laboratory studies both the morphogenetic mechanisms that give rise to the initial limb bud, as well as the earliest positional information that will subsequently be translated into skeletal pattern.  The long term goal of his laboratory is to understand these two fundamental processes well enough in order to enable them to bioengineer a limb bud for therapeutic purposes.

External Funding

  • Canadian Institutes of Health Research
  • March of Dimes Birth Defects Foundation
  • Orthopaedic Research and Education Foundation 


Peer Reviewed


Lau K, Tao H, Liu H, Wen J, Sturgeon K, Sorfazlian N, Wong MD, Lazic S, Li D, Deimling S, 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).

Li D, Sakuma R, Vakili NA, Mo R, Puviindran V, Deimling S, Zhang X, Hopyan S, Hui C- c. Formation of proximal and anterior limb skeleton requires early function of Irx3 and Irx5 and is negatively regulated by Shh signaling. Developmental Cell, 29(2):233-240 (2014).

Wyngaarden LA, Delgado-Olguin P, Su IH, Bruneau BG, Hopyan S. (2011) Ezh2 regulates anteroposterior axis specification and proximodistal axis elongation in the developing limb. Development. 138(17):3759-67.

Wyngaarden LA, Vogeli KM, Ciruna BG, Wells M, Hadjantonakis AK, Hopyan S. (2010) Oriented cell motility and division underlie early limb bud morphogenesis. Development. 137(15): 2551-2558.

Wyngaarden L, Hopyan S. (2008) Plasticity of distal-proximal cell fate in the mammalian limb bud. Developmental Biology. 313(1): 225-33.

Mau E, Whetstone H, Yu C, Hopyan S, Wunder JS, Alman BA. (2007) PTHrP regulates growth plate chondrocyte differentiation and proliferation in a Gli3 dependent manner utilising Hh ligand dependent and independent mechanisms. Developmental Biology. 305(1): 28-39.

Tiet  TD, Hopyan S, Nadesan P, Gokgoz N, Poon R,  Andrulis IL, Alman BA, Wunder JS. (2006) Constitutive hedgehog signaling in chondrosarcoma upregulates tumor cell  proliferation. American Journal of Pathology. 168(1): 321-30.

Hopyan S, Nadesan P, Yu C, Wunder JS, Alman BA. (2005) Dysregulation of hedgehog signaling dysregulation predisposes to synovial chondromatosis.  The Journal of Pathology. 206 (2):143-150.

Hopyan S, Gokgoz N, Poon R, Gensure RC, Yu C, Cole WG, Bell RS, Juppner H, Andrulis IL, Wunder JS, Alman BA. (2002) A mutant PTH/PTHrP type I receptor in enchondromatosis. Nature Genetics. 30 (3): 306-310.

Hopyan S, Gokgoz N, Bell RS, Andrulis IL, Alman BA, Wunder JS. (1999) Expression of Osteocalcin and its transcriptional regulators core-binding factor alpha 1 and Msx2 in osteoid-forming tumours. Journal of Orthopaedic Research. 17(5): 633-638. 


Dodwell E, O'Callaghan J, Anthony A, Jellicoe P, Shah M, Curtis C, Clarke H, Hopyan S. (2012) Combined glenoid anteversion osteotomy and tendon transfers for brachial plexus birth palsy: early outcomes. The Journal of Bone & Joint Surgery. 94(23):2145-52.

Ibrahim T, Howard AW, Murnaghan ML, Hopyan S. (2012) Percutaneous curettage and suction for pediatric extremity aneurysmal bone cysts: is it adequate? Journal of Pediatric Orthopaedics. 32(8):842-7.

Jones KB, Ferguson PC, Lam B, Biau DJ, Hopyan S, Deheshi B, Griffin AM, White LM, Wunder JS. (2012) Effects of neoadjuvant chemotherapy on image-directed planning of surgical resection for distal femoral osteosarcoma. The Journal of Bone & Joint Surgery. 94(15):1399-405.

Canavese F, Wright JG, Cole WG, Hopyan S. (2011) Unicameral bone cysts: comparison of percutaneous curettage, steroid and autologous bone marrow injections. Journal of Pediatric Orthopaedics. 31(1):50-5.

Gupta AA, Pappo A, Saunders N, Edell U, Hopyan S, Ferguson P, Wunder JS, Catton C, O’Sullivan B, Greenberg M, Blackstein M. (2010) Clinical Outcome of Children and Adults with Localized Ewing Sarcoma:  Impact of Chemotherapy Dose and Timing of Local Therapy. Cancer. 116(13): 3189-3194.

Jellicoe P, Son-Hing J, Hopyan S, Thompson GH. (2009) Surgical hip dislocation for removal of intraarticular exostoses: report of two cases. Journal of Pediatric Orthopaedics.  29(4):327-30.

Jellicoe P, Hopyan S. (2008) Can chronic recurrent multifocal osteomyelitis predispose to lymphoma of bone? A case report. Journal of Paediatric Orthopaedics B. 17(6):329-332.

Hopyan S, Tan WJ, Graham HK, Torode IP. (2006) Function and upright time following limb salvage, amputation, and rotationplasty for pediatric sarcoma of bone. Journal of Pediatric Orthopaedics. 26(3):405-8.

Hopyan S, Ngan SYK, Choong PFM. (2005) Natural history of tumour-related sacral obliteration with nerve-root preservation.  Clinical Oncology 17(3):195-198.

Bell RS, Hopyan S, Davis AM, Kandel R, Gross AE. (1997) Sarcoma of the bone - cement membrane: a case report and review of the literature.  Canadian Journal of Surgery. 40(1): 51-55.

Non-Peer Reviewed

Bell RS, Hopyan S, Davis AM, Gross AE. (1993) The occurrence of sarcoma in conjunction with joint arthroplasty.  Current Opinion in Orthopaedics 4: 90-94 (1993).

Book Chapters

Hopyan S. Musculoskeletal Development in Pediatric Orthopaedic Secrets. Ed: Staheli LT, in press

Hopyan S. (2009) Enchondromatosis in Encyclopedic Reference of the Molecular Mechanisms of Disease. Ed: Lang F, Springer, Vienna.

Gupta A, Hopyan S. (2009) What is the Best Treatment of Malignant Bone Tumours in Children in Evidence Based Orthopaedics, Ed: Wright J. Saunders Elsevier, 278-282, Philadelphia.

Hopyan S, Wunder J, Randall L. (2007) Molecular Biology of Tumors in Orthopaedic Knowledge Update, Musculoskeletal Tumors. Ed: Schwartz HS, 13-22. American Academy of Orthopaedic Surgeons, Illinois.

Hopyan S, Alman BA.(2004) Genetics in Orthopaedic Surgery Essentials: Pediatrics. Ed: Cramer KE, Scherl SA, 333-338, Lippincott Williams & Wilkins, New York.