The clinical utility of an SCN1A genetic diagnosis in infantile-onset epilepsy


Dr Sameer M Zuberi at The Paediatric Neurosciences Research Group, Royal Hospital for Sick Children, Glasgow G3 8SJ, UK. E-mail:


Aim  Genetic testing in the epilepsies is becoming an increasingly accessible clinical tool. Mutations in the sodium channel alpha 1 subunit (SCN1A) gene are most notably associated with Dravet syndrome. This is the first study to assess the impact of SCN1A testing on patient management from both carer and physician perspectives.

Method  Participants were identified prospectively from referrals to the Epilepsy Genetics Service in Glasgow and contacted via their referring clinicians. Questionnaires exploring the consequences of SCN1A genetic testing for each case were sent to carers and physicians.

Results  Of the 244 individuals contacted, 182 (75%) carried a SCN1A mutation. Carers of 187 (77%) patients responded (90 females, 97 males; mean age at referral 4y 10mo; interquartile range 9y 1mo). Of those participants whose children tested positive for a mutation, 87% reported that genetic testing was helpful, leading to treatment changes resulting in fewer seizures and improved access to therapies and respite care. Out of 187 physicians, 163 responded (87%), of whom 48% reported that a positive test facilitated diagnosis earlier than with clinical and electroencephalography data alone. It prevented additional investigations in 67% of patients, altered treatment approach in 69%, influenced medication choice in 74%, and, through medication change, improved seizure control in 42%.

Interpretation  In addition to confirming a clinical diagnosis, a positive SCN1A test result influenced treatment choice and assisted in accessing additional therapies, especially in the very young.