The spectrum of SCN1A-related infantile epileptic encephalopathies

Louise A. Harkin, Jacinta M. McMahon, Xenia Iona, Leanne Dibbens, James T. Pelekanos, Sameer M. Zuberi, Lynette G. Sadleir, Eva Andermann, Deepak Gill, Kevin Farrell, Mary Connolly, Thorsten Stanley, Michael Harbord, Frederick Andermann, Jing Wang, Sat Dev Batish, Jeffrey G. Jones, William K. Seltzer, Alison Gardner, The Infantile Epileptic Encephalopathy Referral ConsortiumGrant Sutherland, Samuel F. Berkovic, John C. Mulley, Ingrid E. Scheffer, Chris Lamb

    Research output: Contribution to journalArticlepeer-review

    442 Citations (Scopus)


    The relationship between severe myoclonic epilepsy of infancy (SMEI or Dravet syndrome) and the related syndrome SMEI-borderland (SMEB) with mutations in the sodium channel alpha 1 subunit gene SCN1A is well established. To explore the phenotypic variability associated with SCN1A mutations, 188 patients with a range of epileptic encephalopathies were examined for SCN1A sequence variations by denaturing high performance liquid chromatography and sequencing. All patients had seizure onset within the first 2 years of life. A higher proportion of mutations were identified in patients with SMEI (52/66; 79%) compared to patients with SMEB (25/36; 69%). By studying a broader spectrum of infantile epileptic encephalopathies, we identified mutations in other syndromes including cryptogenic generalized epilepsy (24%) and cryptogenic focal epilepsy (22%). Within the latter group, a distinctive subgroup designated as severe infantile multifocal epilepsy had SCN1A mutations in three of five cases. This phenotype is characterized by early onset multifocal seizures and later cognitive decline. Knowledge of an expanded spectrum of epileptic encephalopathies associated with SCN1A mutations allows earlier diagnostic confirmation for children with these devastating disorders.

    Original languageEnglish
    Pages (from-to)843-852
    Number of pages10
    Issue number3
    Publication statusPublished - Mar 2007


    • Channelopathies
    • Epileptic encephalopathy
    • SCN1A
    • SMEB
    • SMEI


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