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Establishing Biomarkers and Clinical Endpoints in Myotonic Dystrophy Type 1 (END-DM1)


Brief Summary

Building on previous work of the Myotonic Dystrophy Clinical Research Network (DMCRN), the present study seeks to overcome insufficient data on natural history; lack of reliable biomarkers; and incomplete characterization and limited biological understanding of the phenotypic heterogeneity of Myotonic Dystrophy 1 by examining strategies to improve the reliability by making further refinements in our sample collection and analysis procedures by developing strategies for managing patient heterogeneity going forward.

Funding Source- FDA OOPD

Study Type


Healthy Volunteers
Minimum Age
18 Years
Maximum Age
70 Years

Inclusion criteria:

  • Age 18 to 70 (inclusive)
  • Competent to provide informed consent
  • Clinical diagnosis of DM1 based on research criteria1 or positive genetic test
  • Comment: The clinical research criteria require myotonia, muscle weakness in a characteristic distribution, and history of similar findings in a first degree relative. Genetic testing confirmed the diagnosis of DM1 in > 99% of individuals who satisfied these criteria.2

Exclusion criteria:

  • Symptomatic renal or liver disease, uncontrolled diabetes or thyroid disorder, or active malignancy other than skin cancer.
  • Current alcohol or substance abuse
  • Concurrent enrollment in clinical trial for DM1, or participation in trial within 6 months of entry.
  • Concurrent pregnancy or planned pregnancy during the course of the study.
  • Concurrent medical condition that would, in the opinion of the investigator or clinical evaluator, compromise performance on study measures.
  • Note: non-ambulatory participants are not excluded, but are limited to <15% of enrollment.

Inclusion criteria for participants in the muscle biopsy sub-study:

  • Of the 95 patients undergoing the tibialis anterior muscle biopsy, at least half will have at least moderate weakness of ankle dorsiflexion, defined as MRC score ≤ 4+. This is in order to obtain a muscle tissue sample in a person more severely affected with myotonic dystrophy. Approximately 10 patients at each site will undergo the muscle biopsy.

Exclusion criteria for 95 participants in the muscle biopsy sub-study:

  • Known CTG repeat expansion size less than 100 repeats, unless there are clear cut signs of limb weakness and muscle wasting. This is in order to obtain a muscle tissue sample in a person more severely affected with myotonic dystrophy.
  • Use of anticoagulant such as warfarin or a direct oral anticoagulant (e.g. dabigatran) due to the increased risk of bleeding.
  • Use of aspirin or non-steroidal anti-inflammatory agents should be discontinued 3 days prior to the biopsy procedure, if possible.
  • Platelet count <50,000 (if known) due to the increased risk of bleeding.
  • History of a bleeding disorder due to the increased risk of bleeding.
  • Advanced wasting of tibialis anterior (TA) muscle that precludes needle muscle biopsy in order to ensure that a sample taken would be of muscle and not just fat and fascia.
  • Previous muscle biopsy of either TA in order to provide muscle tissue samples of non-biopsied muscles.

Join this Trial

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Study Stats
Protocol No.
Brain/Neurological Diseases
Genetic and Rare Diseases
Musculoskeletal Disorders
Perry Shieh
  • UCLA Westwood
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