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Inherited Myokymia: A Clinical and Genetic Study of a Family

The recruitment status of this study is unknown. The completion date has passed and the status has not been verified in more than two years.
Verified November 2010 by China Medical University Hospital.
Recruitment status was:  Recruiting
Information provided by:
China Medical University Hospital Identifier:
First received: November 29, 2010
Last updated: NA
Last verified: November 2010
History: No changes posted
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.

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

Study Type: Observational
Study Design: Observational Model: Case-Only
Time Perspective: Cross-Sectional
Official Title: Inherited Myokymia: A Clinical and Genetic Study of a Family

Resource links provided by NLM:

Further study details as provided by China Medical University Hospital:

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

Estimated Enrollment: 18
Study Start Date: April 2010
Estimated Primary Completion Date: March 2011 (Final data collection date for primary outcome measure)

Ages Eligible for Study:   Child, Adult, Senior
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:

  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its identifier: NCT01250704

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

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
Study Director: Yi-Ting Hsu, MD China Medical University Hospital
  More Information

Responsible Party: Department of Medical Research, China Medical University Hospital Identifier: NCT01250704     History of Changes
Other Study ID Numbers: DMR99-IRB-190
Study First Received: November 29, 2010
Last Updated: November 29, 2010

Keywords provided by China Medical University Hospital:
Neuromyotonia, Isaac's syndrome; Peripheral nerve hyperexcitability; Myokymia; Potassium channelopathy

Additional relevant MeSH terms:
Isaacs Syndrome
Neuromuscular Manifestations
Neurologic Manifestations
Nervous System Diseases
Signs and Symptoms
Muscular Diseases
Musculoskeletal Diseases
Peripheral Nervous System Diseases
Neuromuscular Diseases processed this record on September 19, 2017