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2005 Fiscal Year Final Research Report Summary

Genetic determination and pathogenesis in thyrotoxic periodic paralysis

Research Project

Project/Area Number 16590836
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Neurology
Research InstitutionKagoshima University

Principal Investigator

ARIMURA Kimiyoshi  Kagoshima University, Graduate School of Medical and Dental Sciences, Associate Professor, 大学院・医歯学総合研究科, 助教授 (20159510)

Co-Investigator(Kenkyū-buntansha) TAKASHIMA Hiroshi  Kagoshima University, Graduate School of Medical and Dental Sciences, Research Associate, 大学院・医歯学総合研究科, 助手 (80372803)
KAMEYAMA Masaki  Kagoshima University, Graduate School of Medical and Dental Sciences, Professor, 大学院・医歯学総合研究科, 教授 (60150059)
Project Period (FY) 2004 – 2005
Keywordsthyrotoxic periodic paralysis / prolonged exercise test / muscle ion channel / voltage-gated potassium channel / polymorphism
Research Abstract

Thyrotoxic periodic paralysis (TPP) is a well known complication of thyrotoxicosis especially in Asian male. The incidence is 1.9% in Japan and 1.8% in China. TPP is seen in 8% of thyrotoxic patients. The diagnosis of TPP is made by the periodic paralysis provoked by heavy meals and exercise, low serum K level and hyperthyroidism. Prolonged exercise test (PET) is positive in most of TPP patients. The pathogenesis of TPP is speculated to be due to the massive shift of potassium into muscle from extra-cellular compartment by hyperactivity of Na/K ATPase pump activity. PET results as well as in vitro microelectrode study in muscle fibers obtained from TPP patients suggest that the pre-existing membrane excitability may be another cause of TPP.
We hypothesize that genetic abnormality of muscle channel ion channel genes may cause in TPP. To date, 4 ion channel genes expressed in skeletal muscle, i.e. CACNA1S, SCN4A, KCNJ2 and KCNE3 have been studied. In this study, we assumed the voltage-gated potassium channel, α-subunit Kv7.5 encoded by KCNQ5 gene to be a candidate gene for TPP, since K+ conductance of patients' muscle was decreased using in vitro microelectrode studies. We analyzed KCNQ5 gene, in addition to the previously examined ion channels, KCNJ2, KCNE3, CACNA1S and SCN4A, in 7 Japanese TPP patients confirmed by the characteristic clinical features and positive PET. DNA analysis showed 5 synonymous SNPs in KCNQ5, KCNJ2, KCNE3 and CACNA1S genes. We could not find a causative variant in the KCNQ5 gene, however, we could not explain the meaning of synonymous SNPs for susceptibility to TPP. Further study such as international collaboration will be needed to have a conclusion of the meaning of synonymous SNPs of ion channel genes.

  • Research Products

    (8 results)

All 2006 2005

All Journal Article (8 results)

  • [Journal Article] Mechanomyographic determination of post-activation potentiation in myopathies2006

    • Author(s)
      Ng AR, Arimura K, et al.
    • Journal Title

      Clin Neurophysiol 117・1

      Pages: 232-9

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] IgM-containing fraction suppressed voltage-gated potassium channels in acquired neuromyotonia.2006

    • Author(s)
      Kurono A, Arimura k, et al.
    • Journal Title

      Acta Neurol Scand 113・3

      Pages: 185-8

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Genetic variability in the extracellular matrix protein as a determinant of risk for developing HTLV-I-associated neurological disease.2006

    • Author(s)
      Nobuhara Y, et al.
    • Journal Title

      Immunogenetics 57・12

      Pages: 944-52

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] Mechanomyo graphic determination of post-activation potentiation in myopathies2006

    • Author(s)
      Ng AR, Arimura K, et al.
    • Journal Title

      Clin Neurophysiol 117(1)

      Pages: 232-239

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] IgM-containing faction suppressed voltage-gated potassium channels in acquired neuromyotonia.2006

    • Author(s)
      Kurono A, Arimura K, et al.
    • Journal Title

      Acta Neurol Scand 113(3)

      Pages: 185-188

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Genetic variability in the extracellular matrix protein as a determinant of risk for developing HTLV-I-associated neurological disease.2006

    • Author(s)
      Nobuhara Y, et al.
    • Journal Title

      Immunogenetics 57(12)

      Pages: 944-952

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] The origin of spontaneous discharges in acquired neuromyotonia. A Macro EMG study.2005

    • Author(s)
      Arimura K, et al.
    • Journal Title

      Clin Neurophysiol 116・8

      Pages: 1835-9

    • Description
      「研究成果報告書概要(和文)」より
  • [Journal Article] The origin of spontaneous discharges in acquired neuromyotonia. A Macro EMG study.2005

    • Author(s)
      Arimura K, et al.
    • Journal Title

      Clin Neurophysiol 116(8)

      Pages: 1835-1839

    • Description
      「研究成果報告書概要(欧文)」より

URL: 

Published: 2007-12-13  

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