A longitudinal study of disease progression in facioscapulohumeral muscular dystrophy (FSHD)

INTRODUCTION/AIMS

In preparation for clinical trials, it is important to better understand how disease burden changes over time in facioscapulohumeral muscular dystrophy (FSHD) and to assess the capability of select metrics to detect these changes. This study aims to evaluate FSHD disease progression over 1 year and to examine the sensitivity of several outcome measures in detecting changes during this interval.

METHODS

We conducted a 12-month prospective observational study of 41 participants with FSHD. Participants were evaluated at baseline, 6 months, and 12 months with serial strength testing (manual muscle testing or MMT and maximum voluntary isometric contraction testing or MVICT), functional testing (FSHD-Composite Outcome Measure or FSHD-COM, FSHD Clinical Severity Score or CSS, and FSHD Evaluation Score or FES), sleep and fatigue assessments, lean body mass measurements, respiratory testing, and the FSHD-Health Index patient-reported outcome. Changes in these outcome measures were assessed over the 12-month period. Associations between changes in outcome measures and both age and sex were also examined.

RESULTS

In a 12-month period, FSHD participant function remained largely stable with a mild worsening of strength, measured by MMT and standardized MVICT scores, and a mild loss in lean body mass.

DISCUSSION

The abilities and disease burden of adults with FSHD are largely static over a 12-month period with participants demonstrating a mild average reduction in some measures of strength. Selection of patients, outcome measures, and trial duration should be carefully considered during the design and implementation of future clinical studies involving FSHD patients.

Lean tissue mass measurements by dual-energy X-ray absorptiometry and associations with strength and functional outcome measures in facioscapulohumeral muscular dystrophy

Facioscapulohumeral muscular dystrophy (FSHD) is a slowly progressive disease of skeletal muscle. Dual energy X-ray absorptiometry (DEXA) is a widely available, cost-effective and sensitive technique for measuring whole body and regional lean tissue mass and has been used in prior clinical trials in neuromuscular diseases. The Clinical Trial Readiness to Solve Barriers to Drug Development in FSHD (ReSolve) study is a prospective, longitudinal, observational multisite study. We obtained concurrent DEXA scans and functional outcome measurements in 185 patients with FSHD at the baseline visit. We determined the associations between lean tissue mass in the upper and lower extremities and corresponding clinical outcome measures. There were moderate correlations between upper and lower extremity lean tissue mass and their corresponding strengths and function. Lean tissue mass obtained by DEXA scan may be useful as a biomarker in future clinical trials in FSHD.

Disease-specific wearable sensor algorithms for profiling activity, gait, and balance in individuals with Charcot-Marie-Tooth disease type 1A

BACKGROUND/AIMS

Charcot-Marie-Tooth Disease type 1A (CMT1A), the most common inherited peripheral neuropathy, is characterized by progressive sensory loss and weakness, which results in impaired mobility. Increased understanding of the genetics and pathophysiology of CMT1A has led to development of potential therapeutic agents, necessitating clinical trial readiness. Wearable sensors may provide useful outcome measures for future trials.

METHODS

Individuals with CMT1A and unaffected controls were recruited for this 12-month study. Participants wore sensors for in-clinic assessments and at-home, from which activity, gait, and balance metrics were derived. Mann-Whitney U tests were used to analyze group differences for activity, gait, and balance parameters. Test-retest reliability of gait and balance parameters and correlations of these parameters with clinical outcome assessments (COAs) were examined.

RESULTS

Thirty individuals, 15 CMT1A, and 15 controls, participated. Gait and balance metrics demonstrated moderate to excellent reliability. CMT1A participants had longer step durations (p < .001), shorter step lengths (p = .03), slower gait speeds (p < .001), and greater postural sway (p < .001) than healthy controls. Moderate correlations were found between CMT-Functional Outcome Measure and step length (r = -0.59; p = .02), and gait speed (r = 0.64; p = .01); 11 out of 15 CMT1A participants demonstrated significant increases in stride duration between the first and last quarter of the 6-min walk test, suggesting fatigue.

INTERPRETATION

In this initial study, gait and balance metrics derived from wearable sensors were reliable and associated with COAs in individuals with CMT1A. Larger longitudinal studies are needed to confirm our findings and evaluate sensitivity and utility of these disease-specific algorithms for clinical trial use.

Antisense oligonucleotide targeting DMPK in patients with myotonic dystrophy type 1: a multicentre, randomised, dose-escalation, placebo-controlled, phase 1/2a trial

BACKGROUND

Myotonic dystrophy type 1 results from an RNA gain-of-function mutation, in which DM1 protein kinase (DMPK) transcripts carrying expanded trinucleotide repeats exert deleterious effects. Antisense oligonucleotides (ASOs) provide a promising approach to treatment of myotonic dystrophy type 1 because they reduce toxic RNA levels. We aimed to investigate the safety of baliforsen (ISIS 598769), an ASO targeting DMPK mRNA.

METHODS

In this dose-escalation phase 1/2a trial, adults aged 20-55 years with myotonic dystrophy type 1 were enrolled at seven tertiary referral centres in the USA and randomly assigned via an interactive web or phone response system to subcutaneous injections of baliforsen 100 mg, 200 mg, or 300 mg, or placebo (6:2 randomisation at each dose level), or to baliforsen 400 mg or 600 mg, or placebo (10:2 randomisation at each dose level), on days 1, 3, 5, 8, 15, 22, 29, and 36. Sponsor personnel directly involved with the trial, participants, and all study personnel were masked to treatment assignments. The primary outcome measure was safety in all participants who received at least one dose of study drug up to day 134. This trial is registered with ClinicalTrials.gov (NCT02312011), and is complete.

FINDINGS

Between Dec 12, 2014, and Feb 22, 2016, 49 participants were enrolled and randomly assigned to baliforsen 100 mg (n=7, one patient not dosed), 200 mg (n=6), 300 mg (n=6), 400 mg (n=10), 600 mg (n=10), or placebo (n=10). The safety population comprised 48 participants who received at least one dose of study drug. Treatment-emergent adverse events were reported for 36 (95%) of 38 participants assigned to baliforsen and nine (90%) of ten participants assigned to placebo. Aside from injection-site reactions, common treatment-emergent adverse events were headache (baliforsen: ten [26%] of 38 participants; placebo: four [40%] of ten participants), contusion (baliforsen: seven [18%] of 38; placebo: one [10%] of ten), and nausea (baliforsen: six [16%] of 38; placebo: two [20%] of ten). Most adverse events (baliforsen: 425 [86%] of 494; placebo: 62 [85%] of 73) were mild in severity. One participant (baliforsen 600 mg) developed transient thrombocytopenia considered potentially treatment related. Baliforsen concentrations in skeletal muscle increased with dose.

INTERPRETATION

Baliforsen was generally well tolerated. However, skeletal muscle drug concentrations were below levels predicted to achieve substantial target reduction. These results support the further investigation of ASOs as a therapeutic approach for myotonic dystrophy type 1, but suggest improved drug delivery to muscle is needed.

FUNDING

Ionis Pharmaceuticals, Biogen.

Accelerate Clinical Trials in Charcot-Marie-Tooth Disease (ACT-CMT): A Protocol to Address Clinical Trial Readiness in CMT1A

With therapeutic trials on the horizon for Charcot-Marie-Tooth type 1A (CMT1A), reliable, valid, and responsive clinical outcome assessments and biomarkers are essential. Accelerate Clinical Trials in CMT (ACT-CMT) is an international study designed to address important gaps in CMT1A clinical trial readiness including the lack of a validated, responsive functional outcome measure for adults, and a lack of validated biomarkers for multicenter application in clinical trials in CMT1A. The primary aims of ACT-CMT include validation of the Charcot-Marie-Tooth Functional Outcome Measure, magnetic resonance imaging of intramuscular fat accumulation as a lower limb motor biomarker, and in-vivo reflectance confocal microscopy of Meissner corpuscle sensory receptor density, a sensory biomarker. Initial studies have indicated that these measures are feasible, reliable and valid. A large prospective, multi-site study is necessary to fully validate and examine the responsiveness of these outcome measures in relation to existing outcomes for use in future clinical trials involving individuals with CMT1A. Two hundred 15 adults with CMT1A are being recruited to participate in this prospective, international, multi-center study. Serial assessments, up to 3 years, are performed and include the CMT-FOM, CMT Exam Score-Rasch, Overall Neuropathy Limitations Scale, CMT-Health Index, as well as nerve conduction studies, and magnetic resonance imaging and Meissner corpuscle biomarkers. Correlations using baseline data will be examined for validity. Longitudinal analyses will document the changes in function, intramuscular fat accumulation, Meissner corpuscle sensory receptor density. Lastly, we will use anchor-based and other statistical methods to determine the minimally clinically important change for these clinical outcome assessments and biomarkers in CMT1A. Reliable, and responsive clinical outcome assessments of function and disease progression biomarkers are urgently needed for application in early and late phase clinical trials in CMT1A. The ACT-CMT study protocol will address this need through the prospective, longitudinal, multicenter examination in unprecedented detail of novel and existing clinical outcome assessments and motor and sensory biomarkers, and enhance international clinical trial infrastructure, training and preparedness for future therapeutic trials in CMT and related neuropathies.

Understanding the Perseverance of the Muscular Dystrophy Community One-Year into the COVID-19 Pandemic

INTRODUCTION

In this study, we examined the long-term social and health impacts of the coronavirus disease 2019 (COVID-19) pandemic on people with muscular dystrophy.

METHODS

We modified our prior COVID-19 Impact Survey to assess impacts from the continuing pandemic using feedback from muscular dystrophy experts, patients, and advocacy group/registry representatives. The survey assessed COVID-19 medical history, and the effects of the pandemic on social aspects, muscle disease, and medical care. We also used the validated 10-item Perceived Stress Scale. The de-identified, electronic survey was distributed to adults with muscular dystrophy via international patient registries and advocacy group websites from February 8, 2021 to March 22, 2021.

RESULTS

Respondents (n = 1243 : 49% Facioscapulohumeral Muscular Dystrophy (FSHD); 43% Myotonic Dystrophy (DM), and 8% Limb-Girdle Muscular Dystrophy (LGMD)) were mostly women and middle-aged (range 18-90 years). Rates of COVID-19 infections were low at 8% with zero deaths. Reported recovery times were also short with only 9% reporting a recovery period greater than eight weeks, and 7% requiring hospitalization with one individual requiring a ventilator. Major challenges reported during the pandemic included: stress management, particularly for those with LGMD, (27%) and wearing a mask (24%). The majority reported a slight worsening in their disease state. Respondents reported moderate stress levels (stress score = 16.4; range = 0-39), with higher stress levels reported by women and those under age 30 years. Seventy-percent of participants who had telemedicine visits were satisfied with the encounters; however, most reported a preference for in-person visits.

CONCLUSIONS

People with MD found ways to manage their stress and overcome obstacles during the COVID-19 pandemic. COVID-19 infection rates and medical complications were similar to a general population. Telemedicine visits may have a more permanent role in care.

Remote assessment of myotonic dystrophy type 1: A feasibility study

INTRODUCTION/AIMS

Remote study visits (RSVs) are emerging as important tools for clinical research. We tested the feasibility of using RSVs to evaluate patients with myotonic dystrophy type 1 (DM1), including remote quantitative assessment of muscle function, and we assessed correlations of remote assessments with patient-reported function.

METHODS

Twenty three subjects with DM1 were consented remotely. Toolkits containing a tablet computer, grip dynamometer, and spirometer were shipped to participants. The tablets were loaded with software for video-conferencing and questionnaires about functional impairment, patient experience with technology, and willingness to participate in future remote studies. Grip strength, forced vital capacity, peak cough flow, timed-up-and-go (TUG), and grip myotonia (hand opening time) were determined during RSVs. We assessed correlations of remote assessments with patient-reported outcomes of muscle function and with CTG repeat size.

RESULTS

All 23 subjects completed RSVs. 95% of participants were able to complete all components of the remote study. All toolkit components were returned upon completion. Grip strength and TUG demonstrated moderate to strong correlations with self-reported inventories of upper and lower extremity impairment, respectively (ρ = 0.7 and ρ = -0.52). A total of 91% of subjects expressed interest in participating in future RSVs.

DISCUSSION

Results of this study support the feasibility of using portable devices and video-conferencing for remote collection of patient-reported outcomes and quantitative assessment of muscle function in DM1.

Consensus Guidelines for Improving Quality of Assessment and Training for Neuromuscular Diseases

Critical components of successful evaluation of clinical outcome assessments (COAs) in multisite clinical trials and clinical practice are standardized training, administration, and documented reliability of scoring. Experiences of evaluators, alongside patient differences from regional standards of care, may contribute to heterogeneity in clinical center’s expertise. Achieving low variability and high reliability of COA is fundamental to clinical research and to give confidence in our ability to draw rational, interpretable conclusions from the data collected. The objective of this manuscript is to provide a framework to guide the learning process for COAs for use in clinics and clinical trials to maximize reliability and validity of COAs in neuromuscular disease (NMD). This is a consensus-based guideline with contributions from fourteen leading experts in clinical outcomes and the field of clinical outcome training in NMD. This framework should guide reliable and valid assessments in NMD specialty clinics and clinical trials. This consensus aims to expedite study start up with a progressive training pathway ranging from research naïve to highly experienced clinical evaluators. This document includes recommendations for education guidelines and roles and responsibilities of key stakeholders in COA assessment and implementation to ensure quality and consistency of outcome administration across different settings.

A Roadmap to Patient Engagement: Facioscapulohumeral Muscular Dystrophy and the ReSolve Clinical Trial

We describe our efforts to overcome barriers to patient engagement in facioscapulohumeral muscular dystrophy (FSHD) and offer a roadmap that can be replicated in other rare neurologic disorders. We implemented an engagement plan during Clinical Trial Readiness to Solve Barriers to Drug Development for FSHD (ReSolve), an 18-month, multisite, observational study of individuals with FSHD. Elements of our engagement plan included conducting focus groups during protocol development, patient involvement on the ReSolve external advisory committee, creation of a patient advisory committee, and collaboration with patient advocacy groups. Patient feedback led to adaptations in the study protocol and to changes in recruitment and retention methods. Patient engagement ensures that the patient voice contributes to multiple aspects of trial design and implementation. Our engagement efforts exemplify how collaboration with patients and families can be accomplished in FSHD and the resultant roadmap process may be replicable in other rare neurologic diseases.

A patient-focused survey to assess the effects of the COVID-19 pandemic and social guidelines on people with muscular dystrophy

Introduction/Aims

In this study, we examined the social and health impacts of the coronavirus disease 2019 (COVID‐19) pandemic and social guidelines on people with muscular dystrophies.

Methods

A prospective de‐identified electronic survey was distributed to adults with self‐reported facioscapulohumeral muscular dystrophy (FSHD), myotonic dystrophy (DM), and limb‐girdle muscular dystrophy (LGMD) enrolled in national registries or with patient advocacy groups.

The COVID‐19 Impact Survey was developed by muscular dystrophy experts in association with patient collaborators and advocacy groups. The Perceived Stress Scale was used to measure perceived stress.

Results

Respondents (n = 774: 56% FSHD; 35% DM, and 9% LGMD) were mostly women and middle‐aged (range 19–87 y). Rates of COVID‐19 infections were low (<1%), compliance with local social distancing guidelines and policies high (98%). Major challenges reported during the pandemic included: obtaining treatment (40%), managing stress (37%), social distancing (36%), and obtaining essentials (34%). The majority reported a slight worsening in their disease state. Respondents reported moderate stress levels (stress score = 15.4; range = 0–35), with higher stress levels reported by women and those under age 30 y. Three‐quarters of participants who participated in telemedicine visits were satisfied with the encounters; however, most reported a preference for in‐person visits.

Discussion

People with muscular dystrophy reported moderate stress and challenges during the COVID‐19 pandemic. Interventions such as exercise and stress‐coping strategies, including strategies specific to women or individuals <30 y, may be important. Further investigation is needed into the role of telemedicine in the care of individuals with muscular dystrophy.

Reliability and validity of the FSHD-composite outcome measure in childhood facioscapulohumeral dystrophy

This study aims to investigate intra-rater reliability and construct validity of the Facioscapulohumeral Dystrophy Composite Outcome Measure (FSHD-COM), in childhood FSHD. Participants included eighteen children with FSHD, and matched healthy controls. Reliability data were collected from 15 participants with FSHD over two testing sessions. Validity data were collected from all participants. Participants with FSHD completed; the FSHD-COM (and modified pediatric version), Motor Function Measure-32 (MFM-32), FSHD Severity Scales, Performance of the Upper Limb 2.0, Pediatric Quality of Life™ Neuromuscular Module and pediatric FSHD Health-Index Questionnaire. Both versions of the FSHD-COM showed excellent intra-rater reliability (ICC_1,2 > 0.99, lower 95%CI > 0.98) with a Minimal Detectable Change (MDC95%) of ≤14.5%. The FSHD-COM had robust and widespread correlations with other related outcome measures. The FSHD-COM versions and 6 min walk test effectively discriminated between children with and without FSHD; the MFM-32 and 10 m walk/run test did not. Ceiling effects were not observed on either version of the FSHD-COM. Reliability and validity findings in this childhood FSHD study concord with estimates in adults. Both versions of the FSHD-COM were effective in discriminating disease in children with mild FSHD symptoms. The FSHD-COM has the potential to be a useful measure of function across the life span.

Longitudinal study of MRI and functional outcome measures in facioscapulohumeral muscular dystrophy

Background

Facioscapulohumeral muscular dystrophy (FSHD) is a patchy and slowly progressive disease of skeletal muscle. For MRI to be a useful biomarker in an FSHD clinical trial, it should reliably detect changes over relatively short time-intervals (~ 1 year). We hypothesized that fatty change over the study course would be most likely in muscles already demonstrating disease progression, and that the degree of MRI burden would be correlated with function.

Methods

We studied 36 patients with FSHD and lower-extremity weakness at baseline. Thirty-two patients returned in our 12-month longitudinal observational study. We analyzed DIXON MRI images of 16 lower-extremity muscles in each patient and compared them to quantitative strength measurement and ambulatory functional outcome measures.

Results

There was a small shift to higher fat fractions in the summed muscle data for each patient, however individual muscles demonstrated much larger magnitudes of change. The greatest increase in fat fraction was observed in muscles having an intermediate fat replacement at baseline, with minimally (baseline fat fraction < 0.10) or severely (> 0.70) affected muscles less likely to progress. Functional outcome measures did not demonstrate marked change over the interval; however, overall MRI disease burden was correlated with functional outcome measures. Direct comparison of the tibialis anterior (TA) fat fraction and quantitative strength measurement showed a sigmoidal relationship, with steepest drop being when the muscle gets more than ~ 20% fatty replaced.

Conclusions

Assessing MRI changes in 16 lower-extremity muscles across 1 year demonstrated that those muscles having an intermediate baseline fat fraction were more likely to progress. Ambulatory functional outcome measures are generally related to overall muscle MRI burden but remain unchanged in the short term. Quantitative strength measurement of the TA showed a steep loss of strength when more fatty infiltration is present suggesting that MRI may be preferable for following incremental change or modulation with drug therapy.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04134-7.

Mexiletine in Myotonic Dystrophy Type 1: A Randomized, Double-Blind, Placebo-Controlled Trial

OBJECTIVE

To assess mexiletine's long-term safety and effect on 6-minute walk distance in a well-defined cohort of patients with myotonic dystrophy type 1 (DM1).

METHODS

We performed a randomized, double-blind, placebo-controlled trial of mexiletine (150 mg 3 times daily) to evaluate its efficacy and safety in a homogenous cohort of adult ambulatory patients with DM1. The primary outcome was change in 6-minute walk distance at 6 months. Secondary outcomes included changes in hand grip myotonia, strength, swallowing, forced vital capacity, lean muscle mass, Myotonic Dystrophy Health Index scores, and 24-hour Holter and ECG results at 3 and 6 months.

RESULTS

Forty-two participants were randomized and 40 completed the 6-month follow-up (n = 20 in both groups). No significant effects of mexiletine were observed on 6-minute walk distance, but hand grip myotonia was improved with mexiletine treatment. There were no differences between the mexiletine and placebo groups with respect to the frequency or type of adverse events. Changes in PR, QRS, and QTc intervals were similar in mexiletine- and placebo-treated participants.

CONCLUSIONS

There was no benefit of mexiletine on 6-minute walk distance at 6 months. Although mexiletine had a sustained positive effect on objectively measured hand grip myotonia, this was not seen in measures reflecting participants' perceptions of their myotonia. No effects of mexiletine on cardiac conduction measures were seen over the 6-month follow-up period.

CLASSIFICATION OF EVIDENCE

This study provides Class I evidence that for ambulatory patients with DM1, mexiletine does not significantly change 6-minute walk distance at 6 months.

The care of patients with Duchenne, Becker, and other muscular dystrophies in the COVID-19 pandemic

The coronavirus disease 2019 (COVID-19) pandemic has resulted in the reorganization of health-care settings affecting clinical care delivery to patients with Duchenne and Becker muscular dystrophy (DBMD) as well as other inherited muscular dystrophies. The magnitude of the impact of this public health emergency on the care of patients with DBMD is unclear as they are suspected of having an increased risk for severe manifestations of COVID-19. In this article, the authors discuss their consensus recommendations pertaining to care of these patients during the pandemic. We address issues surrounding corticosteroid and exon-skipping treatments, cardiac medications, hydroxychloroquine use, emergency/respiratory care, rehabilitation management, and the conduct of clinical trials. We highlight the importance of collaborative treatment decisions between the patient, family, and health-care provider, considering any geographic or institution-specific policies and precautions for COVID-19. We advocate for continuing multidisciplinary care for these patients using telehealth.

Nusinersen for older patients with spinal muscular atrophy: A real-world clinical setting experience

INTRODUCTION

Clinical trials data concerning use of nusinersen in older spinal muscular atrophy (SMA) patients is lacking. We describe our center's experience in using intrathecal nusinersen for older patients in the clinical setting.

METHODS

Retrospective study.

RESULTS

Twelve patients (12-52 years old) were treated with nusinersen. Mean follow-up duration was 17.4 months (range, 4-26 months). All patients had scoliosis; 10 had spinal fusion/instrumentation. All procedures (30 cervical and 57 lumbar punctures) were technically successful. The only side effects were postprocedural headache (9%) and site pain (5.7%). Functional assessments showed stability in 6/9 patients and improvement in 3/9 patients. Subjective improvements in endurance, hand strength, and bulbar functioning critical for activities of daily living were reported in 8/12 patients. None of the patients has discontinued treatment so far.

DISCUSSION

Intrathecal nusinersen can be safely delivered in older SMA patients. Available functional outcome measures are not adequate to capture meaningful subjective improvements.

Clinical trial readiness to solve barriers to drug development in FSHD (ReSolve): protocol of a large, international, multi-center prospective study

Background

Facioscapulohumeral muscular dystrophy (FSHD) is a dominantly-inherited progressive muscular dystrophy caused by de-repression of the DUX4 gene, which causes disease by a toxic-gain-of-function. As molecularly targeted drugs move from preclinical testing into human trials, it is essential that we validate clinical trial tools and methodology to facilitate the drug development process.

Methods/design

The primary goal of this study is to hasten drug development for FSHD by validating two novel clinical outcome assessments (COAs) and refining clinical trial strategies. We will perform an 18-month longitudinal study in 220 genetically confirmed and clinically affected participants using our FSHD Clinical Trial Research Network, comprised of 8 sites in the United States, and 3 collaborating sites in Europe. Visits occur at baseline and months 3, 12, and 18. At each visit we will collect: 1) a novel FSHD functional composite COA made up of 18 evaluator-administered motor tasks in the domains of shoulder/arm, hand, core/abdominal, leg, and balance function; and 2) electrical impedance myography as a novel muscle quality biomarker (US sites). Other COAs include 1) Domain 1 of the Motor Function Measure; 2) Reachable workspace; 3) orofacial strength using the Iowa Oral Performance Instrument; 4) lean muscle mass using dual-energy X-ray absorptiometry (DEXA); 5) strength as measured by quantitative myometry and manual muscle testing; and 6) the FSHD Health Index and other patient-reported outcomes. Plasma, DNA, RNA, and serum will be collected for future biomarker studies. We will use an industry standard multi-site training plan. We will evaluate the test-retest reliability, validity, and sensitivity to disease progression, and minimal clinically important changes of our new COAs. We will assess associations between demographic and genetic factors and the rate of disease progression to inform refinement of eligibility criteria for future clinical trials.

Discussion

To the best of our knowledge, this is the largest collaborative study of patients with FSHD performed in the US and Europe. The results of this study will enable more efficient clinical trial design. During the conduct of the study, relevant data will be made available for investigators or companies pursuing novel FSHD therapeutics.

Trial registration

clinicaltrials.gov NCT03458832; Date of registration: 1/11/2018

Electronic supplementary material

The online version of this article (10.1186/s12883-019-1452-x) contains supplementary material, which is available to authorized users.

Measuring peripheral nerve involvement in Friedreich's ataxia

OBJECTIVE

Experimental therapies under development for Friedreich's Ataxia (FRDA) require validated biomarkers. In-vivo reflectance confocal microscopy (RCM) of skin is a noninvasive way to quantify Meissner's corpuscle (MC) density and has emerged as a sensitive measure of sensory polyneuropathies. We conducted a prospective, cross-sectional study evaluating RCM of MCs and conventional peripheral nerve measures as candidate peripheral nerve markers in FRDA.

METHODS

Sixteen individuals with FRDA and 16 age- and gender-matched controls underwent RCM of MC density and morphology, skin biopsies for epidermal nerve fiber density (ENFD), nerve conduction studies (NCS), and quantitative sensory testing (QST) including touch, vibration, and cooling thresholds.

RESULTS

MC densities were measurable in all participants with FRDA, and were lower at digit V (hand), thenar eminence, and arch (foot) compared to controls. By contrast, sensory NCS showed floor effects and were obtainable in only 13% of FRDA participants. QST thresholds for touch, vibration, and cooling were higher at the hand and foot in FRDA than controls. Reductions in ENFDs were present in more severely affected individuals with FRDA (Friedreich's Ataxia Rating Scale (FARS) >60) compared to matched controls, although skin biopsies were not well tolerated in children. MC densities, ENFDs, and touch and vibration thresholds were associated with clinical disease severity (FARS and modified FARS) and duration since symptom onset.

INTERPRETATION

MC density, ENFD, and QST thresholds provide structural and physiologic markers of sensory involvement in FRDA. Longitudinal evaluation is needed to determine whether these measures can identify changes associated with disease progression or treatment.

Transcriptome alterations in myotonic dystrophy skeletal muscle and heart

Myotonic dystrophy (dystrophia myotonica, DM) is a multi-systemic disease caused by expanded CTG or CCTG microsatellite repeats. Characterized by symptoms in muscle, heart and central nervous system, among others, it is one of the most variable diseases known. A major pathogenic event in DM is the sequestration of muscleblind-like proteins by CUG or CCUG repeat-containing RNAs transcribed from expanded repeats, and differences in the extent of MBNL sequestration dependent on repeat length and expression level may account for some portion of the variability. However, many other cellular pathways are reported to be perturbed in DM, and the severity of specific disease symptoms varies among individuals. To help understand this variability and facilitate research into DM, we generated 120 RNASeq transcriptomes from skeletal and heart muscle derived from healthy and DM1 biopsies and autopsies. A limited number of DM2 and Duchenne muscular dystrophy samples were also sequenced. We analyzed splicing and gene expression, identified tissue-specific changes in RNA processing and uncovered transcriptome changes strongly correlating with muscle strength. We created a web resource at http://DMseq.org that hosts raw and processed transcriptome data and provides a lightweight, responsive interface that enables browsing of processed data across the genome.

Needs management in families affected by childhood-onset dystrophinopathies

Purpose

To collect information about the needs of families affected by childhood-onset dystrophinopathies residing in the United States.

Methods

Individuals with an eligible dystrophinopathy were identified by the Muscular Dystrophy Surveillance, Tracking, and Research network. Between September 2008 and December 2012, 272 caregivers completed a 48-item survey about needs related to information, healthcare services, psychosocial issues, finances, caregiver demographics, and the individual's functioning.

Results

Overall, at least 80% of the survey items were identified as needs for more than one-half of caregivers. Among the needs identified, physical health and access to information were currently managed for most caregivers. Items identified as needed but managed less consistently were funding for needs not covered by insurance and psychosocial support.

Conclusions

Healthcare providers, public health practitioners, and policymakers should be aware of the many needs reported by caregivers, and focus on addressing gaps in provision of needed financial and psychosocial services.

The Charcot-Marie-Tooth Functional Outcome Measure (CMT-FOM)

OBJECTIVE

The purpose of this study was to examine the feasibility, reliability, and convergent validity of the Charcot-Marie-Tooth Functional Outcome Measure (CMT-FOM), a new performance-based measure assessing functional ability in adults with CMT disease.

METHODS

Adults with CMT type 1A (CMT1A) were recruited at the Universities of Rochester and Iowa. Participants were assessed using the CMT-FOM, CMT Exam Score (CMTES), and a symptom report. Test-retest reliability was examined using intraclass correlation coefficients, internal consistency using Cronbach α, and convergent and known-groups validity using Spearman rank analysis and the Mann-Whitney test.

RESULTS

Forty-three individuals (70% women; mean age 41, SD 14.9 years) participated. The CMT-FOM (mean 25.3 ± 8.7, range 12-44/52) was moderately correlated with the CMTES (ρ = 0.62; p < 0.0001) and exhibited acceptable reliability (intraclass correlation coefficient = 0.92) and internal consistency (Cronbach α = 0.81). The CMT-FOM discriminated between participants with clinically mild vs moderate-severe CMT1A. Participants with the mildest CMT1A who demonstrated a floor effect on the CMTES showed functional limitations on the CMT-FOM.

CONCLUSIONS

The CMT-FOM is well tolerated and showed no floor/ceiling effects in an adult CMT1A cohort matching those likely to enter upcoming clinical trials. It appears to be reliable, and our data support convergent and known-groups validity in adults with CMT1A. Longitudinal studies further examining the psychometric properties of the CMT-FOM and its responsiveness to change before its application in therapeutic trials are necessary.

Consensus-based care recommendations for adults with myotonic dystrophy type 1

Purpose of review

Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects between 1 in 3,000 and 8,000 individuals globally. No evidence-based guideline exists to inform the care of these patients, and most do not have access to multidisciplinary care centers staffed by experienced professionals, creating a clinical care deficit.

Recent findings

The Myotonic Dystrophy Foundation (MDF) recruited 66 international clinicians experienced in DM1 patient care to develop consensus-based care recommendations. MDF created a 2-step methodology for the project using elements of the Single Text Procedure and the Nominal Group Technique. The process generated a 4-page Quick Reference Guide and a comprehensive, 55-page document that provides clinical care recommendations for 19 discrete body systems and/or care considerations.

Summary

The resulting recommendations are intended to help standardize and elevate care for this patient population and reduce variability in clinical trial and study environments.

Cervical puncture to deliver nusinersen in patients with spinal muscular atrophy

OBJECTIVE

To report our experience delivering intrathecal nusinersen through cervical puncture in patients with spinal muscular atrophy (SMA) with no lumbar access.

BACKGROUND

SMA is a neuromuscular disorder characterized by profound muscle weakness, atrophy, and paralysis due to degeneration of the anterior horn cells. Nusinersen, the first Food and Drug Administration-approved treatment for SMA, is administered intrathecally via lumbar puncture; however, many patients with SMA have scoliosis or solid spinal fusion with hardware that makes lumbar access impossible. Studies in primates have demonstrated better spinal cord tissue concentration with intrathecal injections than with intracerebral ventricular injections. Therefore we have used C1/C2 puncture as an alternative to administer nusinersen.

METHOD

Retrospective chart review.

RESULTS

Intrathecal nusinersen via cervical puncture was given to 3 patients who had thoracic and lumbosacral spinal fusion: a 12-year-old girl with type 1 SMA and 2 17-year-old girls with type 2 SMA. Cervical puncture was performed without deep sedation under fluoroscopic guidance using a 25-G or a 24-G Whitacre needle in the posterior aspect of C1-C2 interspace and full dose of nusinersen (12 mg/5 mL) was injected after visualizing free CSF flow. Patients completed their 4 loading doses and first maintenance dose of nusinersen, and 15 procedures were successful and well-tolerated.

CONCLUSION

Cervical puncture is a feasible alternative delivery route to administer intrathecal nusinersen in patients with longstanding SMA and spine anatomy precluding lumbar access when done by providers with expertise in this procedure.

Electrical impedance myography in facioscapulohumeral muscular dystrophy: A 1-year follow-up study

INTRODUCTION

Electrical impedance myography (EIM) is a noninvasive technique for measuring muscle composition and a potential physiological biomarker for facioscapulohumeral muscular dystrophy (FSHD).

METHODS

Thirty-two participants with genetically confirmed and clinically affected FSHD underwent EIM in 7 muscles bilaterally. Correlations between EIM and baseline clinical measures were used to select EIM variables of interest in FSHD, and EIM and clinical measures were followed for 1 year.

RESULTS

There were no significant changes in the EIM variables. Although 50-kHZ reactance correlated the strongest with clinical measures at baseline, the 50-211-kHZ phase ratio demonstrated lower within-subject 12-month variability, potentially offering sample size savings for FSHD clinical trial planning.

DISCUSSION

EIM did not identify significant disease progression over 12 months. It is currently unclear whether this is because of limitations of the technology or the slow rate of disease progression in this cohort of FSHD patients over this period of time. Muscle Nerve 58: 213-218, 2018.

Facioscapulohumeral muscular dystrophy functional composite outcome measure

INTRODUCTION

We developed an evaluator-administered functional facioscapulohumeral muscular dystrophy composite outcome measure (FSHD-COM) comprising patient-identified areas of functional burden for future clinical trials.

METHODS

We performed a prospective observational study of 41 patients with FSHD at 2 sites. The FSHD-COM includes functional assessment of the legs, shoulders and arms, trunk, hands, and balance/mobility. We determined the test-retest reliability and convergent validity compared to established FSHD disease metrics.

RESULTS

The FSHD-COM demonstrated excellent test-retest reliability (intraclass correlation coefficient [ICC] 0.96; subscale ICC range, 0.90-0.94). Cross-sectional associations between the FSHD-COM and disease duration, clinical severity, and strength were moderate to strong (Pearson correlation coefficient range |0.51-0.92|).

DISCUSSION

The FSHD-COM is a disease-relevant, functional composite outcome measure suitable for future FSHD clinical trials that shows excellent test-retest reliability and cross-sectional associations to disease measures. Future directions include determining multisite reliability, sensitivity to change, and the minimal clinically important change in the FSHD-COM. Muscle Nerve, 2018.

Validity of the 6 minute walk test in facioscapulohumeral muscular dystrophy

INTRODUCTION

In preparation for future clinical trials, we determined the reliability, relationship to measures of disease severity, and consistency across sites of the 6 Minute Walk Test (6MWT) in patients with facioscapulohumeral muscular dystrophy (FSHD).

METHODS

Genetically defined and clinically affected FSHD participants at 2 sites performed the 6MWT, the Timed Up and Go, and the 30 foot Go/Timed 10 meter test as measures of mobility using standard procedures.

RESULTS

Eight-six participants representing the full range of severity performed the 6MWT. The mean 6MWT distance was 404.3 meters (SD 123.9), with no difference between sites. The 6MWT was reliable (n = 25; intraclass correlation coefficient = 0.99) and demonstrated moderate to strong correlations with lower extremity strength, functional outcomes, and FSHD Clinical Score.

CONCLUSIONS

The 6MWT is reliable and is associated with other measures of FSHD disease severity. Future directions include assessing its sensitivity to disease progression. Muscle Nerve 55: 333-337, 2017.

Electrical impedance myography in facioscapulohumeral muscular dystrophy

INTRODUCTION

In this study we determined the reliability and validity of electrical impedance myography (EIM) in facioscapulohumeral muscular dystrophy (FSHD).

METHODS

We performed a prospective study of EIM on 16 bilateral limb and trunk muscles in 35 genetically defined and clinically affected FSHD patients (reliability testing on 18 patients). Summary scores based on body region were derived. Reactance and phase (50 and 100 kHz) were compared with measures of strength, FSHD disease severity, and functional outcomes.

RESULTS

Participants were mostly men, mean age 53.0 years, and included a full range of severity. Limb and trunk muscles showed good to excellent reliability [intraclass correlation coefficients (ICC) 0.72-0.99]. Summary scores for the arm, leg, and trunk showed excellent reliability (ICC 0.89-0.98). Reactance was the most sensitive EIM parameter to a broad range of FSHD disease metrics.

CONCLUSIONS

EIM is a reliable measure of muscle composition in FSHD that offers the possibility to serially evaluate affected muscles. Muscle Nerve 54: 696-701, 2016.

Myotonic dystrophy health index: Correlations with clinical tests and patient function

INTRODUCTION

The Myotonic Dystrophy Health Index (MDHI) is a disease-specific patient-reported outcome measure. Here, we examine the associations between the MDHI and other measures of disease burden in a cohort of individuals with myotonic dystrophy type-1 (DM1).

METHODS

We conducted a cross-sectional study of 70 patients with DM1. We examined the associations between MDHI total and subscale scores and scores from other clinical tests. Participants completed assessments of strength, myotonia, motor and respiratory function, ambulation, and body composition. Participants also provided blood samples, underwent physician evaluations, and completed other patient-reported outcome measures.

RESULTS

MDHI total and subscale scores were strongly associated with muscle strength, myotonia, motor function, and other clinical measures.

CONCLUSIONS

Patient-reported health status, as measured by the MDHI, is associated with alternative measures of clinical health. These results support the use of the MDHI as a valid tool to measure disease burden in DM1 patients.

Prospective study of muscle cramps in Charcot-Marie-tooth disease

INTRODUCTION

This study aims to assess the frequency, location, severity, duration, and fluctuation over time of muscle cramps in Charcot-Marie-Tooth disease (CMT).

METHODS

Inherited Neuropathies Consortium Contact Registry participants recorded the occurrence and characteristics of muscle cramps using an 11-question survey administered 3 times over 8 weeks.

RESULTS

A total of 110 adult patients with CMT completed the survey. Weekly cramp frequency was 9.3 (SD 12.3), and 23% had daily muscle cramps. Twenty-two percent reported a significant impact on quality of life. Over 8 weeks, the daily frequency and severity of muscle cramps did not change significantly.

CONCLUSIONS

Patients with CMT have muscle cramps that vary little over an 8-week period, and they may interfere with quality of life. These data may be useful in the planning of clinical trials of agents to treat adults with CMT-associated muscle cramps.

Splicing biomarkers of disease severity in myotonic dystrophy

OBJECTIVE

To develop RNA splicing biomarkers of disease severity and therapeutic response in myotonic dystrophy type 1 (DM1) and type 2 (DM2).

METHODS

In a discovery cohort, we used microarrays to perform global analysis of alternative splicing in DM1 and DM2. The newly identified splicing changes were combined with previous data to create a panel of 50 putative splicing defects. In a validation cohort of 50 DM1 subjects, we measured the strength of ankle dorsiflexion (ADF) and then obtained a needle biopsy of tibialis anterior (TA) to analyze splice events in muscle RNA. The specificity of DM-associated splicing defects was assessed in disease controls. The CTG expansion size in muscle tissue was determined by Southern blot. The reversibility of splicing defects was assessed in transgenic mice by using antisense oligonucleotides to reduce levels of toxic RNA.

RESULTS

Forty-two splicing defects were confirmed in TA muscle in the validation cohort. Among these, 20 events showed graded changes that correlated with ADF weakness. Five other splice events were strongly affected in DM1 subjects with normal ADF strength. Comparison to disease controls and mouse models indicated that splicing changes were DM-specific, mainly attributable to MBNL1 sequestration, and reversible in mice by targeted knockdown of toxic RNA. Splicing defects and weakness were not correlated with CTG expansion size in muscle tissue.

INTERPRETATION

Alternative splicing changes in skeletal muscle may serve as biomarkers of disease severity and therapeutic response in myotonic dystrophy.

Muscle weakness in myotonic dystrophy associated with misregulated splicing and altered gating of Ca(V)1.1 calcium channel

Myotonic dystrophy type 1 and type 2 (DM1 and DM2) are genetic diseases in which mutant transcripts containing expanded CUG or CCUG repeats cause cellular dysfunction by altering the processing or metabolism of specific mRNAs and miRNAs. The toxic effects of mutant RNA are mediated partly through effects on proteins that regulate alternative splicing. Here we show that alternative splicing of exon 29 (E29) of Ca(V)1.1, a calcium channel that controls skeletal muscle excitation-contraction coupling, is markedly repressed in DM1 and DM2. The extent of E29 skipping correlated with severity of weakness in tibialis anterior muscle of DM1 patients. Two splicing factors previously implicated in DM1, MBNL1 and CUGBP1, participated in the regulation of E29 splicing. In muscle fibers of wild-type mice, the Ca(V)1.1 channel conductance and voltage sensitivity were increased by splice-shifting oligonucleotides that induce E29 skipping. In contrast to human DM1, expression of CUG-expanded RNA caused only a modest increase in E29 skipping in mice. However, forced skipping of E29 in these mice, to levels approaching those observed in human DM1, aggravated the muscle pathology as evidenced by increased central nucleation. Together, these results indicate that DM-associated splicing defects alter Ca(V)1.1 function, with potential for exacerbation of myopathy.

Urinary dopamine sulfate: regulations and significance in neurological disorders

Dopamine-3-O-sulfate (DA-3-O-S) and dopamine-4-O-sulfate (DA-4-O-S) are important end products of L-dopa metabolism. Therefore they may give indications of disturbances in the peripheral metabolism of catecholamines, when measured in urine samples of patients with Parkinson's disease (PD). In addition, information about the reliability of DA sulfatation after L-dopa therapy may be of significance for its role in the elimination of DA from the peripheral nervous system. Although DA-3-O-S appears to be the predominant sulfo-conjugate in urine, there are no changes in PD nor in depression syndrome compared to controls with or without other neurological disorders. By contrast, DA-4-O-S is significantly decreased in de novo PD subjects. However, a similar reduction is notable in patients with other neurological disorders. In depressed persons the loss of this compound was less pronounced as compared to de novo PD. Treatment with combined L-dopa therapy caused increased excretion of DA-3-O-S, while changes in DA-4-O-S were only marginal. It is concluded that urinary DA-3-O-S cannot be used as marker for PD, while DA-4-O-S is significantly reduced in a variety of neurological disorders and in particular in de novo PD. Further studies are necessary to elucidate its role as possible peripheral marker to distinguish preclinical PD and depression syndrome.

Preparation of dopamine 3-O-sulphate and dopamine 4-O-sulphate as reference substances and high-performance liquid chromatographic trace determination

Simple syntheses of the biologically important but hitherto difficult to obtain dopamine sulpho conjugates dopamine 3-O-sulphate (I) and dopamine 4-O-sulphate (II), as analytical reference substances, starting from dopamine hydrochloride are described. A method for the determination of I and II with reversed-phase high-performance liquid chromatographic separation and coulometric detection in human urine together with calibration and current-voltage curves are presented. Detection limits of approximately 100 pg of I or II and unequivocal substance identifications even in very complex substrates such as human urine are reported.

[Active chickenpox vaccination of children with acute leukemia or other neoplastic diseases]

26 patients with acute leukemia and other malignancies susceptible to varicella were vaccinated during maintenance chemotherapy. Vaccination was done with OKA strain of live attenuated varicella vaccine developed by Takahashi 1974. All recipients showed no adverse clinical reactions. There was no spread of vaccine virus to others. Seroconversion was 94% in seronegative patients. In those having low antibody titers before vaccination in 56% booster effect was demonstrable. None of the seroconverted recipients contracted varicella in spite of documented contact exposure. Vaccine zoster was not observed. The results suggest that in immunocompromised children live varicella vaccination has a protective effect against varicella infection which has a described mortality rate up 7% in this patients.