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1.  Diagnostic Odyssey of Patients with Myotonic Dystrophy 
Journal of neurology  2013;260(10):2497-2504.
The onset and symptoms of the myotonic dystrophies are diverse, complicating their diagnoses and limiting a comprehensive approach to their clinical care. This report analyzes the diagnostic delay (time from onset of first symptom to diagnosis) in a large sample of myotonic dystrophy (DM) patients enrolled in the US National Registry [679 DM type 1 (DM1) and 135 DM type 2 (DM2) patients]. Age of onset averaged 34.0 ± 14.1 years in DM2 patients compared to 26.1 ± 13.2 years in DM1 (p<0.0001). The most common initial symptom in DM2 patients was leg weakness (32.6%) compared to grip myotonia in DM1 (38.3%). Pain was reported as the first symptom in 11.1% of DM2 and 3.0% of DM1 patients (p<0.0001). Reaching the correct diagnosis in DM2 took 14 years on average (double the time compared to DM1) and a significantly higher percentage of patients underwent extended workup including electromyography, muscle biopsies, and finally genetic testing. DM patients who were index cases experienced similar diagnostic delays to non-index cases of DM. Further evaluation of how to shorten these diagnostic delays and limit their impact on burdens of disease, family planning, and symptom management is needed.
PMCID: PMC4162528  PMID: 23807151
myotonic dystrophy; facioscapulohumeral muscular dystrophy; registry; muscular dystrophy; clinical care guidelines
2.  Evoked myotonia can be “dialed-up” by increasing stimulus train length in Myotonic Dystrophy Type 1 
Muscle & nerve  2010;41(2):191-196.
It is unknown how evoked myotonia varies with stimulus frequency or train length, or how it compares to voluntary myotonia in myotonic dystrophy type 1 (DM1).
First dorsal interosseous (FDI) tetanic contractions evoked by trains of 10–20 ulnar nerve stimuli at 10–50 Hz were recorded in 10 DM1 patients and 10 normals. For comparison, maximum voluntary handgrip contractions were also recorded. An automated computer program placed cursors along the declining (relaxation) phase of the force recordings at 90 and 5% of peak force (PF) and calculated relaxation times (RTs) between these points.
For all stimulus frequencies and train lengths, evoked RTs were much shorter, and evoked PFs were much greater in normals than in DM1. In normals, evoked RT was independent of stimulus frequency and train length, while in DM1, RT was longer for train lengths of 20 stimuli (mean:9 seconds in DM1; 0.20 in normals) than for 10 stimuli (mean:3 seconds in DM1, 0.19 in normals), but it did not change with stimulus frequency. In both groups, PF increased greatly as stimulus frequency rose from 10 to 50 Hz but only slightly as train length rose from 10 to 20 stimuli. Voluntary handgrip RT (mean:1.9 seconds) was less than evoked FDI RT (mean:9 seconds).
In DM1, evoked RT can be “dialed up” by increasing stimulus train length. Evoked myotonia testing utilizing a stimulus paradigm of at least 20 stimuli at 30–50 Hz may be useful in anti-myotonic drug trials, particularly when grip RT is normal or equivocal.
PMCID: PMC4122294  PMID: 19750543
myotonia; myotonic dystrophy; handgrip; relaxation time
3.  Reevaluating Measures of Disease Progression in Facioscapulohumeral Muscular Dystrophy 
Neuromuscular disorders : NMD  2013;23(4):306-312.
Recent advances in the understanding of the molecular pathophysiology of facioscapulohumeral muscular dystrophy (FSHD) have identified potential therapeutic targets. Consequently, an accurate understanding of disease progression in FSHD is crucial for the design of future clinical trials. Data from 228 subjects in 3 clinical trials and 1 natural history study were compared to examine disease progression in FSHD. All studies utilized the same techniques for manual muscle testing and maximum voluntary isometric contraction testing. Both techniques yield a total strength score that can be followed over time as an indicator of disease progression. Whereas natural history data showed a decrease in strength over 1 year, there was an apparent increase in strength at 6 months in 2 of the 3 clinical trials in both the placebo and treatment groups, that persisted for up to 1 year for maximum voluntary isometric contraction testing. Variability estimates from the clinical trial data were consistent with those seen in the natural history data. Patients in clinical trials in FSHD may have better outcomes than those in natural history studies, regardless of treatment assignment, emphasizing the importance of placebo groups and the need for caution when interpreting the strength results of controlled and uncontrolled trials.
PMCID: PMC3602208  PMID: 23406877
1. All neuromuscular disease; 2. Muscle disease; 3. Outcome research; 4. All clinical trials; 5. Clinical trials methodology/study design
4.  Prospective cohort study of spinal muscular atrophy types 2 and 3 
Neurology  2012;79(18):1889-1897.
To characterize the natural history of spinal muscular atrophy type 2 and type 3 (SMA 2/3) beyond 1 year and to report data on clinical and biological outcomes for use in trial planning.
We conducted a prospective observational cohort study of 79 children and young adults with SMA 2/3 who participated in evaluations for up to 48 months. Clinically, we evaluated motor and pulmonary function, quality of life, and muscle strength. We also measured SMN2 copy number, hematologic and biochemical profiles, muscle mass by dual x-ray absorptiometry (DXA), and the compound motor action potential (CMAP) in a hand muscle. Data were analyzed for associations between clinical and biological/laboratory characteristics cross-sectionally, and for change over time in outcomes using all available data.
In cross-sectional analyses, certain biological measures (specifically, CMAP, DXA fat-free mass index, and SMN2 copy number) and muscle strength measures were associated with motor function. Motor and pulmonary function declined over time, particularly at time points beyond 12 months of follow-up.
The intermediate and mild phenotypes of SMA show slow functional declines when observation periods exceed 1 year. Whole body muscle mass, hand muscle compound motor action potentials, and muscle strength are associated with clinical measures of motor function. The data from this study will be useful for clinical trial planning and suggest that CMAP and DXA warrant further evaluation as potential biomarkers.
PMCID: PMC3525313  PMID: 23077013
5.  Correlates of Tumor Development in Patients with Myotonic Dystrophy 
Journal of neurology  2012;259(10):2161-2166.
Patients with myotonic dystrophy (DM) have recently been reported to be at increased risk of tumor development, but clinical associations related to this observation are unknown. We calculated the odds ratios (ORs) and 95% confidence intervals (CI) of self-reported tumor development by patients’ demographic and clinical characteristics to evaluate factors associated with tumor development in DM patients, using data from the National Registry of Myotonic Dystrophy and Facioscapulohumeral Dystrophy Patients and Family Members. Of the 911 participants, 47.5% were male and 85.7% had DM type 1 (DM1). Compared with DM1, patients with DM type 2 (DM2) were older at Registry enrollment (median age =55 vs. 44 years, p<0.0001) and at DM diagnosis (median age= 48 vs. 30 years, p<0.0001); and more likely to be females (p=0.001). At enrollment, 95 (10.4%) DM patients reported a history of benign or malignant tumor. Tumors were associated with female gender (OR=1.9, 95% CI=1.2–3.1, p=0.007) and DM1 (OR=2.1, 95% CI=1.1–4.1, p=0.03). In a subgroup analysis of patients with blood-based DNA testing results (397 DM1, 54 DM2), repeat expansion size was not associated with tumor risk in DM1 (p=0.26) or DM2 (p=0.34). In conclusion, female gender and DM1 subtype, but not DNA repeat expansion size, were associated with increased risk of tumors in DM. Follow-up studies are warranted to determine if oncogenes associated with dystrophia myotonica-protein kinase (DMPK) are altered in DM, and to determine if repeat expansion size, as in our study, is not associated with tumor development.
PMCID: PMC3469723  PMID: 22619053
Myotonic dystrophy; comorbidity; neoplasms; risk factors; repeat expansion size
6.  A Quantitative Measure of Handgrip Myotonia in Non-dystrophic Myotonia 
Muscle & nerve  2012;46(4):482-489.
Non-dystrophic Myotonia (NDM) is characterized by myotonia without muscle wasting. A standardized quantitative myotonia assessment (QMA) is important for clinical trials.
Myotonia was assessed in 91 individuals enrolled in a natural history study using a commercially available computerized handgrip myometer and automated software. Average peak force and 90% to 5% relaxation times were compared to historical normal controls studied with identical methods.
30 subjects had chloride channel mutations, 31 sodium channel mutations, 6 DM2, and 24 no identified mutation. Chloride channel mutations were associated with prolonged 1st handgrip relaxation times, and warm up on subsequent handgrips. Sodium channel mutations were associated with prolonged 1st handgrip relaxation times and paradoxical myotonia or warm-up, depending on underlying mutations. DM2 subjects had normal relaxation times but decreased peak force. Sample size estimates are provided for clinical trial planning.
QMA is an automated, non-invasive technique for evaluating myotonia in NDM.
PMCID: PMC3564214  PMID: 22987687
natural history; ion channel mutation; muscle disease; myotonia; non-dystrophic myotonia
7.  Patient-reported impact of symptoms in myotonic dystrophy type 1 (PRISM-1) 
Neurology  2012;79(4):348-357.
To determine the most critical symptoms in a national myotonic dystrophy type 1 (DM1) population and to identify the modifying factors that have the greatest effect on the severity of these symptoms.
We performed a cross-sectional study of 278 adult patients with DM1 from the national registry of patients with DM1 between April and August 2010. We assessed the prevalence and relative significance of 221 critical DM1 symptoms and 14 disease themes. These symptoms and themes were chosen for evaluation based on prior interviews with patients with DM1. Responses were categorized by age, CTG repeat length, gender, and duration of symptoms.
Participants with DM1 provided symptom rating survey responses to address the relative frequency and importance of each DM1 symptom. The symptomatic themes with the highest prevalence in DM1 were problems with hands or arms (93.5%), fatigue (90.8%), myotonia (90.3%), and impaired sleep or daytime sleepiness (87.9%). Participants identified fatigue and limitations in mobility as the symptomatic themes that have the greatest effect on their lives. We found an association between age and the average prevalence of all themes (p < 0.01) and between CTG repeat length and the average effect of all symptomatic themes on participant lives (p < 0.01).
There are a wide range of symptoms that significantly affect the lives of patients with DM1. These symptoms, some previously underrecognized, have varying levels of importance in the DM1 population and are nonlinearly dependent on patient age and CTG repeat length.
PMCID: PMC3400095  PMID: 22786587
8.  SMA-MAP: A Plasma Protein Panel for Spinal Muscular Atrophy 
PLoS ONE  2013;8(4):e60113.
Spinal Muscular Atrophy (SMA) presents challenges in (i) monitoring disease activity and predicting progression, (ii) designing trials that allow rapid assessment of candidate therapies, and (iii) understanding molecular causes and consequences of the disease. Validated biomarkers of SMA motor and non-motor function would offer utility in addressing these challenges. Our objectives were (i) to discover additional markers from the Biomarkers for SMA (BforSMA) study using an immunoassay platform, and (ii) to validate the putative biomarkers in an independent cohort of SMA patients collected from a multi-site natural history study (NHS).
BforSMA study plasma samples (N = 129) were analyzed by immunoassay to identify new analytes correlating to SMA motor function. These immunoassays included the strongest candidate biomarkers identified previously by chromatography. We selected 35 biomarkers to validate in an independent cohort SMA type 1, 2, and 3 samples (N = 158) from an SMA NHS. The putative biomarkers were tested for association to multiple motor scales and to pulmonary function, neurophysiology, strength, and quality of life measures. We implemented a Tobit model to predict SMA motor function scores.
12 of the 35 putative SMA biomarkers were significantly associated (p<0.05) with motor function, with a 13th analyte being nearly significant. Several other analytes associated with non-motor SMA outcome measures. From these 35 biomarkers, 27 analytes were selected for inclusion in a commercial panel (SMA-MAP) for association with motor and other functional measures.
Discovery and validation using independent cohorts yielded a set of SMA biomarkers significantly associated with motor function and other measures of SMA disease activity. A commercial SMA-MAP biomarker panel was generated for further testing in other SMA collections and interventional trials. Future work includes evaluating the panel in other neuromuscular diseases, for pharmacodynamic responsiveness to experimental SMA therapies, and for predicting functional changes over time in SMA patients.
PMCID: PMC3615018  PMID: 23565191
9.  If you build a rare disease registry, will they enroll and will they use it? Methods and data from the National Registry of Myotonic Dystrophy (DM) and Facioscapulohumeral Muscular Dystrophy (FSHD) 
Contemporary Clinical Trials  2011;33(2):302-311.
Registries are becoming increasingly important for rare diseases as experimental therapies develop. This report describes the methodology behind the National Registry of Myotonic Dystrophy (DM) and Facioscapulohumeral Muscular Dystrophy (FSHD) Patients and Family Members to facilitate the development of other rare disease registries. We also highlight data about the pathophysiology and select burdens of DM and FSHD reported at baseline and longitudinally.
The Registry consists of de-identified, patient reported information collected at baseline and annually and information from review of medical records. Investigators can use the Registry to analyze de-identified data and to facilitate recruitment into clinical studies.
To date, the Registry has enrolled 1611 members, facilitated 24 studies, and collected data annually for up to 8 years. Genetic test results were obtained in 56.2% of enrollees. Approximately one-third of members used assistive devices and another one-third reported psychological problems at baseline. Wheelchair use was reported for both short and long distances by 7.0% of DM and 18.1% of FSHD members. Approximately 60% of members reported their employment was affected by their disease.
Strengths of the Registry include large sample sizes, stringent review of clinical and molecular data, annually updated information, and regular interactions between patients and investigators. Registry data provide new insights into the burdens of DM and FSHD, such as, psychological problems and reduced employment. Opportunities abound for investigators to utilize Registry resources to assess the impact of these and other burdens on health care costs, progression of symptoms, and quality of life.
PMCID: PMC3357007  PMID: 22155025
Myotonic dystrophy; Facioscapulohumeral muscular dystrophy; Registry; Disease progression; Burdens of disease
10.  Laboratory Abnormalities in Patients with Myotonic Dystrophy Type 2 
Archives of neurology  2011;68(9):1180-1184.
Myotonic dystrophy type-2 (DM2) is a recently discovered adult muscular dystrophy. Similar to DM1, this disease causes progressive debilitating weakness, clinical myotonia, and early cataracts, and is thought to cause widespread physiologic dysfunction of multiple organ systems.
To analyze and compile the laboratory abnormalities of patients with DM2.
Baseline DM2 laboratory data were compiled representing 68 different types of laboratory tests and 1442 total studies.
University Medical Center.
Eighty-three adults with genetically confirmed or clinically probable DM2 were identified. Of these patients, 49 had documented baseline laboratory screening.
Main Outcome Measures
The individual frequencies of abnormal values in the population with DM2 studied.
Of the 1442 studies, results for 359 (24.9%) were outside of their standard reference ranges. Of the 68 types of laboratory tests studied, 43 had values from fifteen or more different patients with DM2. The relative frequency of an abnormally elevated laboratory value was greater than 50% in several tests, including the levels of creatine kinase, total cholesterol, lactate dehydrogenase, and alanine aminotransferase (ALT). In addition, serum levels of immunoglobulin G (IgG) were low in 75% of all DM2 patients tested and absolute lymphocyte counts were low in 54% of all DM2 patients tested.
There is a high frequency of laboratory abnormalities in patients with DM2. These abnormalities provide insight into the widespread pathologic manifestations of DM2 and may form a basis for clinical monitoring and disease screening.
PMCID: PMC3429333  PMID: 21911698
11.  An Open-Label Trial of Recombinant Human Insulin-Like Growth Factor-I/Recombinant Human Insulin-Like Growth Factor Binding Protein-3 (rhIGF-1/rhIGFBP-3) in Myotonic Dystrophy Type 1 
Archives of Neurology  2010;68(1):37-44.
To evaluate the safety and tolerability of recombinant human insulin-like growth factor-1 (rhIGF-1) complexed with IGF binding protein-3 (rhIGF-1/rhIGFBP-3) in patients with myotonic dystrophy type 1 (DM1).
Open-label dose-escalation clinical trial.
University medical center.
Fifteen moderately affected ambulatory participants with genetically-proven DM1.
Participants received escalating dosages of subcutaneous rhIGF-1/rhIGFBP-3 over 24 weeks followed by a 16 week washout period.
Outcome Measures
Serial assessments of safety, muscle mass, muscle function, and metabolic state were performed. The primary outcome variable was the ability of participants to complete 24 weeks on rhIGF-1/rhIGFBP-3 treatment.
All participants tolerated rhIGF-1/rhIGFBP-3. There were no significant changes in muscle strength or functional outcomes measures. Lean body muscle mass measured by dual energy x-ray absorptiometry increased by 1.95 kg (p=0.0007) after treatment. Participants also experienced a mean reduction in triglyceride levels of 47 mg/dL (p=0.002), a mean increase in HDL levels of 5.0 mg/dL (p=0.03), a mean reduction in HbA1c of 0.15% (p=0.03), and a mean increase in testosterone level (in men) of 203 ng/dL (p=0.002) while on rhIGF-1/rhIGFBP-3. Mild reactions at the injection site occurred (n=9 participants), as did mild transient hypoglycemia (n=3), lightheadedness (n=2), and transient papilledema (n=1).
rhIGF-1/rhIGFBP-3 treatment was generally well tolerated in DM1. rhIGF-1/rhIGFBP-3 was associated with increased lean body mass and improvements in metabolism, but not with increased muscle strength or function. Larger randomized controlled trials would be needed to further evaluate the efficacy and safety of this medication in patients with neuromuscular disease.
PMCID: PMC3374954  PMID: 20837825
12.  Hypothesis: neoplasms in myotonic dystrophy 
Cancer causes & control : CCC  2009;20(10):2009-2020.
Tumorigenesis is a multi-step process due to an accumulation of genetic mutations in multiple genes in diverse pathways which ultimately lead to loss of control over cell growth. It is well known that inheritance of rare germline mutations in genes involved in tumorigenesis pathways confer high lifetime risk of neoplasia in affected individuals. Furthermore, a substantial number of multiple malformation syndromes include cancer susceptibility in their phenotype. Studies of the mechanisms underlying these inherited syndromes have added to the understanding of both normal development and the pathophysiology of carcinogenesis. Myotonic dystrophy (DM) represents a group of autosomal dominant, multisystemic diseases that share the clinical features of myotonia, muscle weakness, and early-onset cataracts. Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) result from unstable nucleotide repeat expansions in their respective genes. There have been multiple reports of tumors in individuals with DM, most commonly benign calcifying cutaneous tumors known as pilomatricomas. We provide a summary of the tumors reported in DM and a hypothesis for a possible mechanism of tumorigenesis. We hope to stimulate further study into the potential role of DM genes in tumorigenesis, and help define DM pathogenesis, and facilitate developing novel treatment modalities.
PMCID: PMC3110730  PMID: 19642006
Tumorigenesis; Myotonic dystrophy; Repeat expansion disorders; Pilomatricoma; β-Catenin

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