Clinical Implementation and Outcomes of Genetic Testing for Epilepsy by the Ontario Epilepsy Genetic Testing Program

Tugce B Balci; Laila C Schenkel; Cassandra Rastin; Kevin Jones; Lysa Boissé Lomax; Jacob Turowec; Jennifer Kerkhof; Pratibha Bhai; Olga Jarinova; Stacy Hewson; A Narayan Prasad; O Carter Snead 3rd; David A Dyment; Bekim Sadikovic

doi:10.1017/cjn.2025.69

Clinical Implementation and Outcomes of Genetic Testing for Epilepsy by the Ontario Epilepsy Genetic Testing Program

Can J Neurol Sci. 2025 Apr 14:1-12. doi: 10.1017/cjn.2025.69. Online ahead of print.

Authors

Tugce B Balci^{1

2}, Laila C Schenkel^{3

4}, Cassandra Rastin³, Kevin Jones⁵, Lysa Boissé Lomax⁶, Jacob Turowec³, Jennifer Kerkhof³, Pratibha Bhai³, Olga Jarinova^{7

8}, Stacy Hewson⁹, A Narayan Prasad¹⁰, O Carter Snead 3rd¹¹, David A Dyment¹², Bekim Sadikovic^{3

4}

Affiliations

¹ Division of Genetics, Department of Paediatrics, Western University, London, ON, Canada.
² Medical Genetics Program of Southwestern Ontario, London Health Sciences Centre, London, ON, Canada.
³ Molecular Diagnostics Program and the Verspeeten Clinical Genome Centre, London Health Sciences Centre, London, ON, Canada.
⁴ Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada.
⁵ Division of Pediatric Neurology Department of Pediatrics McMaster University, Hamilton, ON, Canada.
⁶ Division of Neurology Department of Medicine Queen's University, Kingston, ON, Canada.
⁷ Department of Pathology and Laboratory Medicine, University of Ottawa, Ottawa, ON, Canada.
⁸ Department of Genetics, CHEO, Ottawa, ON, Canada.
⁹ Department of Genetic Counselling, The Hospital for Sick Children, Toronto; Department of Molecular Genetics, University of Toronto, Toronto, ON, Canada.
¹⁰ Clinical Neurological Sciences, Department of Pediatrics, Western University London, ON, Canada.
¹¹ Department of Paediatrics, University of Toronto, Toronto, ON, Canada.
¹² Children's Hospital of Eastern Ontario Research Institute, University of Ottawa, Ottawa, ON, Canada.

PMID: 40222906
DOI: 10.1017/cjn.2025.69

Abstract

Background: Epilepsy is a relatively common condition that affects approximately 4-5 per 1000 individuals in Ontario, Canada. While genetic testing is now prevalent in diagnostic and therapeutic care plans, optimal test selection and interpretation of results in a patient-specific context can be inconsistent and provider dependent.

Methods: The first of its kind, the Ontario Epilepsy Genetic Testing Program (OEGTP) was launched in 2020 to develop clinical testing criteria, curate gene content, standardize the technical testing criteria through a centralized testing laboratory, assess diagnostic yield and clinical utility and increase genetics literacy among providers.

Results: Here we present the results of the first two years of the program, demonstrating the overall 20.8% diagnostic yield including pathogenic sequence and copy number variation detected by next-generation sequencing panels. Routine follow-up testing of family members enabled the resolution of ambiguous findings. Post-test outcomes were collected as reported by the ordering clinicians, highlighting the clinical benefits of genetic testing.

Conclusion: This programmatic approach to genetic testing in epilepsy by OEGTP, together with engagement of clinical and laboratory stakeholders, provided a unique opportunity to gather insight into province-wide implementation of a genetic testing program.

Keywords: diagnostics; epilepsy; next-generation sequencing.