Skip to Main Content Go to Sitemap

Gregory Costain

Title: Staff Physician, Division of Clinical and Metabolic Genetics
Designations: MD, PhD
Alternate Contact Name: Denese Henry
Alternate Phone: 416-813-7654 ext. 301480
Alternate Email:
U of T Positions: Assistant Professor, Department of Paediatrics

Research Positions

Scientist-Track Investigator
Genetics & Genome Biology


Dr. Gregory Costain is a physician-scientist who specializes in the diagnosis of rare genetic conditions in children. He joined the Division of Clinical and Metabolic Genetics at SickKids as a staff physician in 2020 after completing his residency training at the University of Toronto.

He runs a specialized Neuropsychiatric Genetics Clinic at SickKids. He is also a Scientist-Track Investigator in Genetics and Genome Biology, in the SickKids Research Institute. His research program is focused on understanding the causes and consequences of rare variation in the human genome. His lab uses genome sequencing to discover new disease genes and genotype-phenotype associations, in a setting of an undiagnosed paediatric disease program.

Education and experience

  • 20032006: Bachelor of Science, Mathematics, Honours, Queen’s University, Kingston, ON
  • 20062008: Master of Science, Mathematics, McGill University, Montreal, QC
  • 20082015: Doctor of Medicine/ Doctor of Philosophy, Medical Science, University of Toronto, Toronto, ON
  • 20152020: Fellow of The Royal College of Physicians of Canada, Medical Genetics, University of Toronto, Toronto, ON


  • 2011: Vanier Canada Graduate Scholarship - Canadian Institutes of Health Research
  • 2013: Institute of Genetics Lap-Chee Tsui Publication Award - Canadian Institutes of Health Research
  • 2019: Division of Clinical and Metabolic Genetics Joe T.R. Clarke Award - SickKids
  • 2019: Department of Paediatrics CanMEDS Competencies Award - University of Toronto


  1. Lionel AC, Costain G, Monfared N, Walker S, Reuter MS, Hosseini SM, Thiruvahindrapuram B, Merico D, Jobling R, Nalpathamkalam T, Pellecchia G, Sung WWL, Wang Z, Bikangaga P, Boelman C, Carter MT, Cordeiro D, Cytrynbaum C, Dell SD, Dhir P, Dowling JJ, Heon E, Hewson S, Hiraki L, Inbar-Feigenberg M, Klatt R, Kronick J, Laxer RM, Licht C, MacDonald H, Mercimek-Andrews S, Mendoza-Londono R, Piscione T, Schneider R, Schulze A, Silverman E, Siriwardena K, Snead OC, Sondheimer N, Sutherland J, Vincent A, Wasserman JD, Weksberg R, Shuman C, Carew C, Szego MJ, Hayeems RZ, Basran R, Stavropoulos DJ, Ray PN, Bowdin S, Meyn MS, Cohn RD, Scherer SW, Marshall CR. Improved diagnostic yield compared to targeted gene sequencing panels suggests a role for whole-genome sequencing as a first-tier genetic test. Genetics in Medicine. 2018; 20(4): 435-443. 
  2. Costain G,  Walker S, Argiropoulos B, Baribeau DA, Bassett AS, Boot E, Devriendt K, Kellam B, Marshall CR, Prasad A, Serrano MA, Stavropoulos DJ, Twede H, Vermeesch JR, Vorstman JAS, Scherer SW. Rare copy number variations affecting the synaptic gene DMXL2 in neurodevelopmental disorders. Journal of Neurodevelopmental Disorders. 2019; 11(1): 3. 
  3. Costain G, Cordeiro D, Matviychuk D, Mercimek-Andrews S. Clinical application of targeted next-generation sequencing panels and whole exome sequencing in childhood epilepsy. Neuroscience. 2019; 418: 291-310. 
  4. Costain G, Callewaert B, Gabriel H, Tan TT, Walker S, Christodoulou J, Lazar T, Menten B, Orkin J, Sadedin S, Snell M, Vanlander A, Vergult S, White SM, Scherer SW, Hayeems RZ, Blaser S, Wodak SJ, Chitayat D, Marshall CR, Meyn MS. De novo missense variants in RAC3 cause a novel neurodevelopmental syndrome. Genetics in Medicine. 2019; 21(4): 1021-1026. 
  5. Costain G, Ghosh MC, Maio N, Carnevale A, Si YC, Rouault TA, Yoon G. Absence of iron-responsive element-binding protein 2 causes a novel neurodegenerative syndrome. Brain. 2019; 142(5): 1195-1202. 
Back to Top