An observational study in Myotonic Dystrophy 1 and DM1, sponsored by Virginia Commonwealth University. Recruiting at 17 sites in 7 countries. Open to participants aged 18 Years to 70 Years. Per ClinicalTrials.gov, last updated 2026-06-10.
Sponsored by Virginia Commonwealth University · Observational
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
Approximately 700 adult participants (18 to 70 years old, inclusive) with DM1 will be enrolled at 15 centers (up to 70 patients will be recruited at each site). No treatment will be administered as part of this study. Participants will receive standard of care as determined by the investigators. Study visits occur at baseline/0 months, 12 months, and 24 months. Few restrictions are placed on participation in the study because the investigators aim to capture the full spectrum of disease severity.
Muscle biopsy sub-study: Studies of splicing biomarkers in muscle biopsy samples will be conducted on a subset of 95 participants. These participants will have an additional study visit at 3 months.
Longitudinal muscle biopsy sub-study: Up to 30 individuals who have had a prior muscle biopsy as part of a DMCRN study will be asked to undergo another biopsy greater than 24 months after the prior biopsy. These participants will have an additional ad hoc biopsy visit.
COVID-19 sub-study: To evaluate severity of illness and response to COVID-19 vaccination in DM1 patients compared to corresponding data available about the general population, END-DM1 study participants will be asked to complete a one-time survey about COVID-19 experiences. A subset of those participants' blood samples will be analyzed to understand immunoglobulin response to infection and vaccination in DM1 patients.
Actigraphy sub-study: To assess daily physical activity in individuals with DM1 and evaluate physical activity changes over a 12-24 month period related to disease progression, a subset of participants will be asked to wear a small, wireless activity monitor while performing functional assessments described in the main study. Those participants will be asked to wear the activity monitor for 7 days following their research visit. Those participants will be asked to complete additional questionnaires.
Handheld Dynamometry sub-study: To evaluate additional muscle strength methods, a subset of participants will be asked to complete additional strength testing using either the MEDup or MicroFET handheld dynamometry device on the same day as their END-DM1 main study visit. Those participants will be asked to return to the clinic for a second visit within 10 days of the END-DM1 study visit to repeat the handheld dynamometry assessments and complete additional strength measures.
125 studies on the registry are indexed under Myotonic Dystrophy; 51 are open to participants now.
This study's planned enrollment of 700 is above the median of 100 across 56 observational studies indexed under Myotonic Dystrophy.
Browse Myotonic Dystrophy studies →Virginia Commonwealth University is the lead sponsor of 641 studies on the registry; 82 are open to participants now.
Of its 88 completed or terminated interventional studies of FDA-regulated products, 62 (70%) have results posted.
Counted across the registry records on this site, refreshed daily.
DM1 has a prevalence rate of approximately 1 per 2,300. There are no expected gender differences. Both men and women will be selected for this study.
Children with DM1 are not included in this project because the pathophysiological basis of congenital and childhood DM1 appears to be mechanistically distinct.
Exclusion criteria:
Inclusion criteria for participants in the muscle biopsy sub-study:
Exclusion criteria for 95 participants in the muscle biopsy sub-study:
Patients will receive standard of care as determined by their treating physician. Study visits occur at baseline/0 months, 12 months, and 24 months
Change in ambulation over 24 months as measured by the 10 meter walk (m/s).
10 meter walk will be measured (m/s)
Time frame: 12 and 24 months
Change in respiratory function over 24 months as measured by spirometry, specifically the supine forced vital capacity (FVC).
Supine forced vital capacity (% predicted)
Time frame: 12 and 24 months
Percent splicing of DM1-affected splice events
RNA sequenced of muscle biopsy samples collected at two different times will be combined and used to calculate a percent splicing index (PMI)
Time frame: 3 months
Longitudinal Muscle Biopsy Sub-study: Characterization of RNA splicing measures over a prolonged period of time (>24 months)
RNA sequenced of muscle biopsy samples collected at two different times will be combined and used to calculate a percent splicing index (PMI)
Time frame: 24 months
Longitudinal Muscle Biopsy Sub-study: Characterization of functional endpoints over a prolonged period of time (>24 months)
10-meter walk/run, grip strength, ADF (ankle dorsiflexion) strength, supine FVC (forced vital capacity)
Time frame: 24 months
COVID-19 Sub-study: Data from DM1 patients or caregivers about COVID-19 illness and vaccination experience, severity of illness and response to vaccination in DM1 patients compared to corresponding data available about the general population.
To evaluate the severity and rate of COVID-19 infection in patients with DM1 compared to the general population symptomatic response to COVID-19 vaccination in DM1 patients
Time frame: 24 months
COVID-19 Sub-study: Immunoglobulin profile and measles titers, and COVID-19 IgG titers
To understand immunoglobulin response to infection and vaccination in DM1 patients
Time frame: 24 months
Actigraphy Sub-study: Feasibility of measuring daily physical activity in individuals with DM1 in a multi-site study
Participants will be asked to wear an activity monitor for 7 days following their in-clinic END-DM1 study visit to evaluate whether this type of activity monitoring is feasible in future trials.
Time frame: 24 months
Actigraphy Sub-study: Objective daily physical activity using wireless accelerometry (ActiGraph), and comparison to normative values and patient reported physical activity.
Participants will be asked to wear an activity monitor for 7 days following their in-clinic END-DM1 study visit and report physical activity, to establish physical activity data in the DM1 population.
Time frame: 24 months
Actigraphy Sub-study: Physical activity changes over a 12-24 month period related to disease progression.
Participants will wear the wireless activity monitor during the functional and strength measures, and complete additional study questionnaires at their regular END-DM1 study visits.
Time frame: 24 months
Handheld Dynamometry Sub-study: Inter-rater reliability, standard error of measurement, and minimal detectable change of Maximal Isometric Muscle Strength force values obtained with the MEDup and MicroFET handheld dynamometers in adults with DM1
Participants will be assessed using either the MEDup or MicroFET handheld dynamometer on the same day as an END-DM1 main study visit. Participants will complete a second visit +/- 10 days from that visit where HHD will be assessed using the same HHD method (either MEDup or MicroFET) used at the HHD visit. Additional functional and strength assessments will be captured at this visit.
Time frame: 24 months
Handheld Dynamometry Sub-study: Comparison of quantitative muscle strength testing feasibility and validity between MEDup and MicroFET with the existing Fixed-QMT currently used in the END-DM1 study protocol.
Data captured for MEDup and MicroFET will be compared to data collected using the Fixed-QMT measures in the main END-DM1 study.
Time frame: 24 months
Plan to share: No — Aggregated and deidentified data will be shared with qualified investigators upon majority approval of the DMCRN investigators.
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