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Inherited Myokymia: A Clinical and Genetic Study of a Family

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01250704
Recruitment Status : Unknown
Verified November 2010 by China Medical University Hospital.
Recruitment status was:  Recruiting
First Posted : December 1, 2010
Last Update Posted : December 1, 2010
Information provided by:
China Medical University Hospital

Brief Summary:
Neuromyotonia (NMT), so called Isaac's syndrome, is a rare disorder in which hyperexcitability of peripheral motor nerves leads to intermittent muscle contractions. It is characterized by muscle twitching at rest (visible myokymia), cramps, hyperhidrosis, paraesthesiae, mild muscle weakness. and impaired muscle relaxation, or pseudomyotonia. Electromyographic recording is a key diagnostic tool in detecting myokymia and neuromyotonia. Pathophysiology of neuromyotonia is claimed to be related immune disorder, autoimmune anti-voltage-gated potassium-channel antibodies and genetic mutation in potassium channel. KCNA1 (Kv1.1) mutation was mostly reported in a autosomal dominant trait. In the present study, we report a family affected with myokymia,worsening with elevated body temperature, febrile illness or spicy food. How the change in temperature influence clinical features of channelopathies is an interesting topic. Variant clinical severity of family members are recorded. The index patient has possible autoimmune mechanism involvement because of his clinical feature of myasthenia gravis with thymoma and hyperthyroidism. Further analyzing the genetic mutation in potassium channelopathy may provide researchers some pathophysiological insight into the Isaac's syndrome.

Condition or disease
A Study of Clinical and Genetic Mutations in a Family of Neuromyotonia, so Called Isaac's Syndrome

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Study Type : Observational
Estimated Enrollment : 18 participants
Observational Model: Case-Only
Time Perspective: Cross-Sectional
Official Title: Inherited Myokymia: A Clinical and Genetic Study of a Family
Study Start Date : April 2010
Estimated Primary Completion Date : March 2011

Biospecimen Retention:   Samples With DNA
Genomic DNA was extracted from each patient's peripheral blood leukocytes using Genomaker DNA extraction kit (Blossom, Taipei, Taiwan). The complete KCNA1 coding region, including the intron/exon boundaries, was amplified according to the procedure reported by Imbrici et al

Information from the National Library of Medicine

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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
We interview and examine the family members directly at our hospital and home visit or indirectly by telephone visit.

Inclusion Criteria:

  • The disease was initially diagnosed of Isaacs syndrome by two neurologist(Dr Tsai and Dr Yang). We will recruit family members of diseased patient and normal subjects for clinical, electromyographic and genetic studies.

Exclusion Criteria:

  • none

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01250704

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Contact: Yi-ting Hsu, MD 886-4-22062121 ext 5039

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China Medical University Hospital Not yet recruiting
Taichung, Taiwan, 404
Contact: Chon-Haw Tsai, MD, PhD    886-4-22062121 ext 5030   
Principal Investigator: Yi-Ting Hsu, MD         
Principal Investigator: Chon-Haw Tsai, MD,PhD         
Principal Investigator: Yu-Wan Yang, MD,MS         
Principal Investigator: FUU-JEN Tsai, MD, PhD         
China medical university hospital Recruiting
Taichung, Taiwan, 404
Contact: Yi-ting Hsu, MD    886-4-22062121 ext 5039   
China medical university hospital Recruiting
Taichung, Taiwan, 404
Sponsors and Collaborators
China Medical University Hospital
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Study Director: Yi-Ting Hsu, MD China Medical University Hospital

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Responsible Party: Department of Medical Research, China Medical University Hospital Identifier: NCT01250704     History of Changes
Other Study ID Numbers: DMR99-IRB-190
First Posted: December 1, 2010    Key Record Dates
Last Update Posted: December 1, 2010
Last Verified: November 2010
Keywords provided by China Medical University Hospital:
Neuromyotonia, Isaac's syndrome; Peripheral nerve hyperexcitability; Myokymia; Potassium channelopathy
Additional relevant MeSH terms:
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Isaacs Syndrome
Neuromuscular Manifestations
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Muscular Diseases
Musculoskeletal Diseases
Peripheral Nervous System Diseases
Neuromuscular Diseases