SCN1A mutations and epilepsy

Authors

  • John C. Mulley,

    1. Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia
    2. School of Molecular and Biomedical Sciences, University of Adelaide, Adelaide, South Australia, Australia
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  • Ingrid E. Scheffer,

    1. Epilepsy Research Centre and Department of Medicine (Neurology), University of Melbourne, Melbourne, Victoria, Australia
    2. Austin Health, Melbourne, Victoria, Australia
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  • Steven Petrou,

    1. Howard Florey Institute of Experimental Physiology and Medicine, University of Melbourne, Melbourne, Victoria, Australia
    2. Bionomics Ltd., Adelaide, South Australia, Australia
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  • Leanne M. Dibbens,

    1. Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia
    2. Department of Paediatrics, University of Adelaide, Adelaide, South Australia, Australia
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  • Samuel F. Berkovic,

    1. Epilepsy Research Centre and Department of Medicine (Neurology), University of Melbourne, Melbourne, Victoria, Australia
    2. Austin Health, Melbourne, Victoria, Australia
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  • Louise A. Harkin

    Corresponding author
    1. Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, South Australia, Australia
    2. Department of Paediatrics, University of Adelaide, Adelaide, South Australia, Australia
    • Department of Genetic Medicine, Women's and Children's Hospital, North Adelaide, SA 5006, Australia
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  • Communicated by Henrik Dahl

Abstract

SCN1A is part of the SCN1A-SCN2A-SCN3A gene cluster on chromosome 2q24 that encodes for α pore forming subunits of sodium channels. The 26 exons of SCN1A are spread over 100 kb of genomic DNA. Genetic defects in the coding sequence lead to generalized epilepsy with febrile seizures plus (GEFS+) and a range of childhood epileptic encephalopathies of varied severity (e.g., SMEI). All published mutations are collated. More than 100 novel mutations are spread throughout the gene with the more debilitating usually de novo. Some clustering of mutations is observed in the C-terminus and the loops between segments 5 and 6 of the first three domains of the protein. Functional studies so far show no consistent relationship between changes to channel properties and clinical phenotype. Of all the known epilepsy genes SCN1A is currently the most clinically relevant, with the largest number of epilepsy related mutations so far characterized. Hum Mutat 25:535–542, 2005. © 2005 Wiley-Liss, Inc.

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