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“Jerky” dystonia in children: Spectrum of phenotypes and genetic testing

Authors

  • Friedrich Asmus MD,

    1. Department of Neurodegenerative Disease, Hertie-Institute for Clinical Brain Research, Center of Neurology, University of Tuebingen, Tuebingen, Germany
    2. Department of General Neurology, Hertie-Institute for Clinical Brain Research, Center of Neurology, University of Tuebingen, Tuebingen, Germany
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  • Annette Langseth MD,

    1. Department of Paediatric Neurology, The Children's University Hospital, Temple Street, Dublin, Ireland
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  • Elaine Doherty MSc,

    1. Department of Paediatric Neurology, The Children's University Hospital, Temple Street, Dublin, Ireland
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  • Therese Nestor RSCN, RGN, CNS,

    1. Department of Paediatric Neurology, The Children's University Hospital, Temple Street, Dublin, Ireland
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  • Marita Munz,

    1. Department of Neurodegenerative Disease, Hertie-Institute for Clinical Brain Research, Center of Neurology, University of Tuebingen, Tuebingen, Germany
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  • Thomas Gasser MD,

    1. Department of Neurodegenerative Disease, Hertie-Institute for Clinical Brain Research, Center of Neurology, University of Tuebingen, Tuebingen, Germany
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  • Tim Lynch FRCPI, FRCP,

    1. Department of Neurology, Mater Misericordiae University Hospital, Dublin, Ireland
    2. Conway Institute of Biomolecular and Biomedical Research, University College, Dublin, Ireland
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  • Mary D. King FRCPI, FRCPCH

    Corresponding author
    1. Department of Paediatric Neurology, The Children's University Hospital, Temple Street, Dublin, Ireland
    • Department of Paediatric Neurology, The Children's University Hospital, Temple Street, Dublin 1, Ireland
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  • Potential conflict of interest: None.

Abstract

Hyperkinetic dystonia is characterized by phasic, tremulous, and “jerky” movements in addition to twisting postures. We studied longitudinally 23 index patients with hyperkinetic dystonia from a quaternary pediatric movement disorder clinic in Ireland. Four clinical categories emerged: (1) Eight patients were diagnosed with myoclonus-dystonia, of whom seven carried heterozygous epsilon sarcoglycan (SGCE) mutations, including a novel deletion of exon 10. Gait disorder, unsteadiness, or frequent falls before 18 months were detected in all SGCE mutation carriers, whereas the typical neck-predominant presentation developed only years later. (2) One patient classified as benign hereditary chorea, because jerks were choreiform and continuous rather than action-induced, carried a heterozygous stop mutation of the TITF-1 gene (Y114X, exon 2). (3) Three mutation-negative patients were grouped as “myoclonic dystonia” with jerks only in the body regions affected by dystonia. (4) Eleven patients presented with a novel combination of dystonia and low amplitude poly-mini myoclonus of the upper limbs and pectoral muscles (D-PMM). In early childhood up to 3 years of age, an initial presentation with predominant gait impairment with only subtle jerks should prompt consideration of SGCE mutation analysis in addition to testing for DYT1 mutations. A causative gene for D-PMM remains to be identified. © 2008 Movement Disorder Society

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