Contractile Properties of Hypertrofic Muscles in Patients With Non-Dystrophic Myotonia

Brief Title

Contractile Properties of Hypertrofic Muscles in Patients With Non-Dystrophic Myotonia

Official Title

Contractile Properties of Hypertrofic Muscles in Patients With Non-Dystrophic Myotonia

Brief Summary

      In myotonia congenita (MC), mutations in the CLCN1 gene coding a key chloride channel
      expressed in muscle cells cause myotonia. On examination, the myotonia can be demonstrated as
      delayed muscle relaxation of muscle contractions after mechanical stimulations. Existing
      literature describe no muscle weakness in MC patients, however a recent muscle MRI study in
      non-dystrophic myotonia patients found structural abnormalities in affected muscles when
      examined using T1 and STIR imaging. The question remains whether the signs of structural
      changes in the muscle are merely due to the myotonia, or long-term effects of elevated stress
      of the tissue, and if so, whether those changes lead to clinically significant loss of
      contractile properties of the muscle.

      This study examines if the contractile properties of myotonic muscles are impaired in MC
      patients. 40 patients with Thomsens disease (n=20) and Beckers disease (n=20), respectively,
      will be included along with 20 healthy controls. Peak muscle torque is measured in the hand
      by hand dynamometer and in the thigh and calf muscles with a Biodex System 4 Pro Dynamometer
      and the cross-sectional area of the muscles are examined on T1-weighed and Dixon-MRI-scan.
      With the obtained data peak torque in strength tests, muscle hypertrophy, fat fraction in
      muscle tissue and contractility of the muscles, compared with healthy controls, will be

Study Type


Primary Outcome

Contractile properties

Secondary Outcome

 Measuring muscle hypertrophy in upper and lower limbs


Non-Dystrophic Myotonia

Study Arms / Comparison Groups

Description:  MC patients with either dominant (Thomsens) or recessive (Becker) myotonia.


* Includes publications given by the data provider as well as publications identified by National Clinical Trials Identifier (NCT ID) in Medline.

Recruitment Information

Estimated Enrollment


Start Date

February 1, 2021

Completion Date

December 1, 2021

Primary Completion Date

December 1, 2021

Eligibility Criteria

        Inclusion Criteria:

          -  Age <18 years

          -  Molecularly verified MC (Thomsens or Beckers disease)

        Exclusion Criteria:

          -  Conditions that may impair results of the study, evaluated by the investigator

          -  Clausphobia

          -  Pregnancy or breastfeeding

          -  Metallic objects in and around the body that are not MR-compatible




18 Years - 80 Years

Accepts Healthy Volunteers



Laura Jacobsen, BSc, +4535456135, [email protected]

Location Countries


Location Countries


Administrative Informations



Organization ID


Responsible Party

Principal Investigator

Study Sponsor

Rigshospitalet, Denmark

Study Sponsor

Laura Jacobsen, BSc, Principal Investigator, Rigshospitalet, Denmark

Verification Date

March 2021