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

Management of motor rehabilitation in individuals with muscular dystrophies. 1st Consensus Conference report from UILDM - Italian Muscular Dystrophy Association (Rome, January 25-26, 2019)

Muscular dystrophy (MD) is a group of neuromuscular diseases characterized by progressive muscle weakness due to various mutations in several genes involved in muscle structure and function. The age at onset, evolution and severity of the different forms of MD can vary and there is often impairment of motor function and activities of daily living. Although there have been important scientific advances with regard to pharmacological therapies for many forms of MD, rehabilitation management remains central to ensuring the patient's psychophysical well-being. Here we report the results of an Italian consensus conference promoted by UILDM (Unione Italiana Lotta alla Distrofia Muscolare, the Italian Muscular Dystrophy Association) in order to establish general indications and agreed protocols for motor rehabilitation of the different forms of MD.

Metabolic complications in myotonic dystrophy type 1: A cross-sectional survey using the National Registry of Japan

Myotonic dystrophy type 1 (DM1) is the most common form of muscular dystrophy in adults, affecting multiple organs, including the eyes, heart, endocrine system, and central nervous system. The broad spectrum of DM1 symptoms has been attributed to the aberrant pre-mRNA splicing of various genes due to an abnormal expansion of the CTG repeat in the 3' untranslated region of the DMPK gene. The current challenge in the clinical care of DM1 is the lack of well-established protocols for the management of each organ disorder or symptom. Moreover, the current status of clinical management has not been adequately explored. Metabolic disturbance in DM1 has been less explored among the DM1 manifestations, even though impaired glucose tolerance is a widely known metabolic disorder associated with DM1. We investigated the metabolic disturbance related to DM1 using the national registry of neuromuscular diseases in Japan, Registry of Muscular Dystrophy (Remudy), and assessed the metabolic complications in DM1 and the current treatments. We obtained comprehensive information on the current status of liver dysfunction and dyslipidemia in a sizeable DM1 cohort (~300). We confirmed that the incidence of liver dysfunction and dyslipidemia, particularly hypertriglyceridemia, as well as impaired glucose tolerance, were significantly higher in DM1 patients. Furthermore, the majority of DM1 patients with dyslipidemia were not receiving pharmacotherapy. Our data highlight the current status of DM1 patients in Japan, which can guide the establishment of the standard of care for metabolic issues consequent to DM1.

New developments in myotonic dystrophies from a multisystemic perspective

PURPOSE OF REVIEW

The multisystemic involvement of myotonic dystrophies (DMs) intricates disease monitoring, patients' care and trial design. This update of the multifaceted comorbidities observed in DMs aims to assist neurologists in the complex management of patients and to encourage further studies for still under-investigated aspects of the disease.

RECENT FINDINGS

We reviewed the most recent studies covering pathogenesis and clinical aspects of extra-muscular involvement in DM1 and DM2. The largest body of evidence regards the cardiac and respiratory features, for which experts' recommendations have been produced. Gastrointestinal symptoms emerge as one of the most prevalent complaints in DMs. The alteration of insulin signaling pathways, involved in gastrointestinal manifestations, carcinogenesis, muscle function, cognitive and endocrinological aspects, gain further relevance in the light of recent evidence of metformin efficacy in DM1. Still, too few studies are performed on large DM2 cohorts, so that current recommendations mainly rely on data gathered in DM1 that cannot be fully translated to DM2.

SUMMARY

Extra-muscular manifestations greatly contribute to the overall disease burden. A multidisciplinary approach is the key for the management of patients. Consensus-based recommendations for DM1 and DM2 allow high standards of care but further evidence are needed to implement these recommendations.

Myotonic dystrophy type1: 13years of experience at a tertiary hospital. Clinical and epidemiological study and genotype-phenotype correlation

INTRODUCTION

The incidence of myotonic dystrophy type1 (DM1), a disease with great phenotypic variety, in our region is unknown. This study aims to estimate the incidence of DM1 at our hospital (a reference centre in Aragon, Spain) and to identify the characteristics of our population (genotype-phenotype correlation).

METHODS

Retrospective, descriptive study of 459 patients classified according to the number of CTG repeats, as follows: normal (5-35), premutation (36-50), protomutation (51-80), small expansions (81-150), intermediate expansions (151-1000), and large expansions (>1000). Furthermore, according to clinical phenotype, patients were categorised as unaffected (5-50 CTG repeats), mild form or asymptomatic (51-150), classical form (151-1000), and severe form (>1000).

RESULTS

The incidence of DM1 was 20.61 cases per million person-years (95%CI: 19.59-21.63). An inverse correlation was observed between the number of CTG repeats and the age at genetic diagnosis (ρ=-0.547; 95%CI: -0.610 to -0.375; P<.001). CTG5 was the most frequent polymorphic allele in healthy individuals. Of all patients with DM1, 28.3% presented the mild or asymptomatic form, 59.1% the classical form, and 12.6% the severe form. Inheritance was maternal in 35.1% of cases, paternal in 59.4%, and uncertain in 5.5%. In mild forms, frontal balding in men was the most prevalent phenotypic trait, as well as myotonia and cataracts, while in the classical form, ptosis, facial weakness, voice and pronunciation alterations, myotonia, and fatigue/sleepiness were most frequent.

CONCLUSIONS

The incidence of DM1 in Aragon is significant. Multidisciplinary study of the phenotype of patients with DM1 is key to early diagnosis and personalised management.

Integrative Cell Type-Specific Multi-Omics Approaches Reveal Impaired Programs of Glial Cell Differentiation in Mouse Culture Models of DM1

Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder caused by a non-coding CTG repeat expansion in the DMPK gene. This mutation generates a toxic CUG RNA that interferes with the RNA processing of target genes in multiple tissues. Despite debilitating neurological impairment, the pathophysiological cascade of molecular and cellular events in the central nervous system (CNS) has been less extensively characterized than the molecular pathogenesis of muscle/cardiac dysfunction. Particularly, the contribution of different cell types to DM1 brain disease is not clearly understood. We first used transcriptomics to compare the impact of expanded CUG RNA on the transcriptome of primary neurons, astrocytes and oligodendrocytes derived from DMSXL mice, a transgenic model of DM1. RNA sequencing revealed more frequent expression and splicing changes in glia than neuronal cells. In particular, primary DMSXL oligodendrocytes showed the highest number of transcripts differentially expressed, while DMSXL astrocytes displayed the most severe splicing dysregulation. Interestingly, the expression and splicing defects of DMSXL glia recreated molecular signatures suggestive of impaired cell differentiation: while DMSXL oligodendrocytes failed to upregulate a subset of genes that are naturally activated during the oligodendroglia differentiation, a significant proportion of missplicing events in DMSXL oligodendrocytes and astrocytes increased the expression of RNA isoforms typical of precursor cell stages. Together these data suggest that expanded CUG RNA in glial cells affects preferentially differentiation-regulated molecular events. This hypothesis was corroborated by gene ontology (GO) analyses, which revealed an enrichment for biological processes and cellular components with critical roles during cell differentiation. Finally, we combined exon ontology with phosphoproteomics and cell imaging to explore the functional impact of CUG-associated spliceopathy on downstream protein metabolism. Changes in phosphorylation, protein isoform expression and intracellular localization in DMSXL astrocytes demonstrate the far-reaching impact of the DM1 repeat expansion on cell metabolism. Our multi-omics approaches provide insight into the mechanisms of CUG RNA toxicity in the CNS with cell type resolution, and support the priority for future research on non-neuronal mechanisms and proteomic changes in DM1 brain disease.

Myotonic dystrophy type 1 drug development: A pipeline toward the market

Myotonic dystrophy type 1 (DM1) is a multisystemic neuromuscular genetic disease with an estimated prevalence of approximately at least half a million individuals based on its vast ethnic variation. Building upon a well-known physiopathology and several proof-of-concept therapeutic approaches, herein we compile a comprehensive overview of the most recent drug development programs under preclinical and clinical evaluation. Specifically, close to two dozen drug developments, eight of which are already in clinical trials, explore a diversity of new chemical entities, drug repurposing, oligonucleotide, and gene therapy-based approaches. Of these, repurposing of tideglusib, mexiletine, or metformin appear to be therapies with the most potential to receive marketing authorization for DM1.

Management of respiratory complications and rehabilitation in individuals with muscular dystrophies: 1st Consensus Conference report from UILDM - Italian Muscular Dystrophy Association (Milan, January 25-26, 2019)

Respiratory complications are common in the patient with muscular dystrophy. The periodic clinical and instrumental respiratory evaluation is extremely important. Despite the presence in the literature of updated guidelines, patient associations often report lack of knowledge of these pathologies, particularly in peripheral hospitals. The purpose of this work, inspired by the Italian Muscular Dystrophy Association (UILDM) is to improve management of respiratory problems necessary for the management of these patients complex. To this end, the main items that the specialist can meet in the follow-up of these pathologies have been analyzed and discussed, among which the respiratory basal evaluation, the criteria of adaptation to non-invasive ventilation, management of bronchial secretions, situations of respiratory emergency, indications for tracheostomy and the subject of advance directives of treatment (DAT).

A Normal Electrocardiogram Does Not Exclude Infra-Hisian Conduction Disease in Patients With Myotonic Dystrophy Type 1

OBJECTIVES

This study aimed to identify electrocardiographic (ECG) predictors of a prolonged His-ventricular (HV) interval in patients with type 1 myotonic dystrophy (DM1).

BACKGROUND

Patients with DM1 have an increased risk of sudden cardiac death. The presence of His-Purkinje system disease/prolonged HV interval (≥70 ms) is associated with a higher risk of potentially life-threatening bradyarrhythmic events.

METHODS

Electrophysiology studies (EPSs) were performed in all DM1 patients referred to 2 tertiary centers for routine cardiac assessment. In a subgroup of patients, the EPS was repeated at varying intervals.

RESULTS

A total of 154 patients (mean age: 43.7 ± 13.3; 58.1% male) underwent 202 diagnostic EPSs. HV ≥70 ms was found on 58 EPSs (28.7%); 9 of 59 patients (15.2%) with PR <200 ms and QRS interval <110 ms on baseline ECG had an HV ≥70 ms on EPS. Among those with PR ≥200 ms and/or QRS interval ≥100 ms, only 33.9% had an HV ≥70 ms on EPS. There were 38 patients who underwent repeated EPS, in which 28.8% demonstrated a prolongation of the HV interval overall compared with baseline. QRS duration demonstrated the most powerful discriminative capacity for HV ≥70 ms (area under the receiver operating characteristic curve: 0.76; 95% confidence interval [CI]: 0.68 to 0.84; p < 0.001). On multivariate analysis, QRS interval ≥112 ms had the highest predictive value for HV ≥70 ms (odds ratio: 7.94; 95% CI: 3.85 to 16.37.

CONCLUSIONS

ECG parameters have a poor predictive value for infra-Hisian conduction block in DM1 patients. QRS and PR intervals are normal in up to 15.2% of DM1 patients with prolonged HV, and 66.1% of those with PR ≥200 ms and/or QRS ≥100 ms do not have advanced His-Purkinje conduction system disease on EPS. Electrophysiology testing should be a mandatory part of screening for all patients to guide prophylactic pacemaker implantation.

Metabolic Alterations in Myotonic Dystrophy Type 1 and Their Correlation with Lipin

Myotonic dystrophy type 1 (DM1) is an autosomal dominant hereditary and multisystemic disease, characterized by progressive distal muscle weakness and myotonia. Despite huge efforts, the pathophysiological mechanisms underlying DM1 remain elusive. In this review, the metabolic alterations observed in patients with DM1 and their connection with lipin proteins are discussed. We start by briefly describing the epidemiology, the physiopathological and systemic features of DM1. The molecular mechanisms proposed for DM1 are explored and summarized. An overview of metabolic syndrome, dyslipidemia, and the summary of metabolic alterations observed in patients with DM1 are presented. Patients with DM1 present clinical evidence of metabolic alterations, namely increased levels of triacylglycerol and low-density lipoprotein, increased insulin and glucose levels, increased abdominal obesity, and low levels of high-density lipoprotein. These metabolic alterations may be associated with lipins, which are phosphatidate phosphatase enzymes that regulates the triacylglycerol levels, phospholipids, lipid signaling pathways, and are transcriptional co-activators. Furthermore, lipins are also important for autophagy, inflammasome activation and lipoproteins synthesis. We demonstrate the association of lipin with the metabolic alterations in patients with DM1, which supports further clinical studies and a proper exploration of lipin proteins as therapeutic targets for metabolic syndrome, which is important for controlling many diseases including DM1.

Predictors of respiratory decline in myotonic dystrophy type 1 (DM1): a longitudinal cohort study

We studied 33 patients affected by juvenile and adult myotonic dystrophy type 1 (DM1). The aim of the study was to assess clinical and laboratory parameters that could predict the requirement of noninvasive ventilation (NIV) in DM1. Secondary outcome was to assess the interplay between genetic profile, muscle impairment severity and presence of cardiac comorbidities.Patients with genetic diagnosis of DM1 were recruited. An abnormal trinucleotide repeat (CTG) expansion of dystrophy protein kinase gene (DMPK) on chromosome 19q13.3 was the prerequisite for inclusion. The number of triplet repeats was measured in genomic DNA to classify subjects. A multidisciplinary team evaluated the patients every 6-8 months up to 18 years with serial cardiological and respiratory function assessments. Neurological progression was monitored using a validated DM1-specific rating scale (MIRS). Independent variables considered for the study outcomes were gender, genetic status, age of presentation, MIRS scores, and results of pulmonary function tests (PFTs).Patients were 17 males (51.5%) and 16 females (48.5%). 16 cases were younger than mean age of 31.4 years, the remaining 17 were up to 65. 12 subjects (36.4%) underwent NIV during follow up. Cardiac comorbidities were detected in 63.6% of cases and in 91% of patients in NIV. Among PFTs, forced vital capacity (FVC) was a reliable indicator of respiratory decline. FVC values were significantly associated with clinical muscle severity assessed by MIRS.Severity of muscular impairment, CTG expansion size, age and presence of cardiac comorbidities predict respiratory impairment in DM1.

Characterization of cannabis use by patients with myotonic dystrophy type 1: A pilot study

The treatment of myotonic dystrophy type 1 (DM1) focuses on reducing symptom burden. However, since medication often fails to produce satisfying symptom relief, some patients seek alternatives, such as cannabis, to help reduce some of these symptoms. The aim of this study was to provide an accurate profile of cannabis use among DM1 patients. Phone interviews were conducted to identify current and former users, and to assess reasons for cannabis use. Characteristics of cannabis use were also investigated. Briefly, among the 72 study participants, 22.2% currently used cannabis and a majority of them (56.9%) reported using it to relieve symptoms associated with DM1. These users, classified as therapeutic users, reported poorer health status (EQ-5D index scores: 0.532±0.230 vs. 0.823±0.208, p = 0.020; EQ-VAS scale 50.56±10.74 vs. 75.57±21.50, p = 0.009) than non-therapeutic users. Finally, differences among sex were also highlighted. While the therapeutic effects of cannabis were not explored in our study, our results support the potential role of cannabis and cannabinoids in the treatment of DM1-associated symptoms which will need to be thoroughly investigated.

Lesion distribution and substrate of white matter damage in myotonic dystrophy type 1: Comparison with multiple sclerosis

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The supratentorial distribution of lesions is similar in DM1 and MS.

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Patients with DM1 do not show infratentorial lesions.

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Quantitative magnetization transfer supports the presence of demyelination in DM1 lesions, but not in the NAWM.

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Anterior temporal lobe lesions in DM1 might have a different substrate than periventricular ones.

Myotonic Dystrophy type 1 (DM1) is an autosomal dominant condition caused by expansion of the CTG triplet repeats within the myotonic dystrophy protein of the kinase (DMPK) gene. The central nervous system is involved in the disease, with multiple symptoms including cognitive impairment. A typical feature of DM1 is the presence of widespread white matter (WM) lesions, whose total volume is associated with CTG triplet expansion. The aim of this study was to characterize the distribution and pathological substrate of these lesions as well as the normal appearing WM (NAWM) using quantitative magnetization transfer (qMT) MRI, and comparing data from DM1 patients with those from patients with multiple sclerosis (MS). Twenty-eight patients with DM1, 29 patients with relapsing-remitting MS, and 15 healthy controls had an MRI scan, including conventional and qMT imaging. The average pool size ratio (F), a proxy of myelination, was computed within lesions and NAWM for every participant. The lesion masks were warped into MNI space and lesion probability maps were obtained for each patient group. The lesion distribution, total lesion load and the tissue-specific mean F were compared between groups. The supratentorial distribution of lesions was similar in the 2 patient groups, although mean lesion volume was higher in MS than DM1. DM1 presented higher prevalence of anterior temporal lobe lesions, but none in the cerebellum and brainstem. Significantly reduced F values were found within DM1 lesions, suggesting a loss of myelin density. While F was reduced in the NAWM of MS patients, it did not differ between DM1 and controls. Our results provide further evidence for a need to compare histology and imaging using new MRI techniques in DM1 patients, in order to further our understanding of the underlying disease process contributing to WM disease.

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.

Neurological complications of cardiomyopathies

There is a multifaceted relationship between the cardiomyopathies and a wide spectrum of neurological disorders. Severe acute neurological events, such as a status epilepticus and aneurysmal subarachnoid hemorrhage, may result in an acute cardiomyopathy the likes of Takotsubo cardiomyopathy. Conversely, the cardiomyopathies may result in a wide array of neurological disorders. Diagnosis of a cardiomyopathy may have already been established at the time of the index neurological event, or the neurological event may have prompted subsequent cardiac investigations, which ultimately lead to the diagnosis of a cardiomyopathy. The cardiomyopathies belong to one of the many phenotypes of complex genetic diseases or syndromes, which may also involve the central or peripheral nervous systems. A number of exogenous agents or risk factors such as diphtheria, alcohol, and several viruses may result in secondary cardiomyopathies accompanied by several neurological manifestations. A variety of neuromuscular disorders, such as myotonic dystrophy or amyloidosis, may demonstrate cardiac involvement during their clinical course. Furthermore, a number of genetic cardiomyopathies phenotypically incorporate during their clinical evolution, a gamut of neurological manifestations, usually neuromuscular in nature. Likewise, neurological complications may be the result of diagnostic procedures or medications for the cardiomyopathies and vice versa. Neurological manifestations of the cardiomyopathies are broad and include, among others, transient ischemic attacks, ischemic strokes, intracranial hemorrhages, syncope, muscle weakness and atrophy, myotonia, cramps, ataxia, seizures, intellectual developmental disorder, cognitive impairment, dementia, oculomotor palsies, deafness, retinal involvement, and headaches.

Gender effect on cardiac involvement in myotonic dystrophy type 1

BACKGROUND AND PURPOSE

Cardiac involvement is observed in about 80% of subjects with myotonic dystrophy type 1 (DM1) and is mainly characterized by cardiac conduction and/or rhythm abnormalities (CCRAs), possibly leading to sudden cardiac death (SCD). Our objective was to investigate whether the gender difference may influence the cardiac involvement and SCD in DM1.

METHODS

We analyzed prevalence and incidence of cardiological abnormalities in males versus females in 151 consecutive DM1 patients over a 35-year follow-up period.

RESULTS

Fifty-five patients, 35 males (62.5%) and 20 females (42.5%), developed some type of CCRA during the follow-up period (mean 7.82 ± 6.21 years). CCRA overall, and specifically cardiac conduction abnormalities (CCAs), were significantly more frequent in males than in females (p = 0.043 and p = 0.031, respectively). CCRAs progressed in 16 males (45.7%) and six females (30%). Twenty-four patients, 14 males (25.0%) and 10 females (21.3%), died during the follow-up. Nine of them, six males (10.7%) and three females (6.4%), had SCD. After correction for Muscular Impairment Rating Scale progression, cytosine thymine-guanine expansion, and follow-up duration, a higher prevalence of CCAs was independently associated with male gender (p = 0.039), but independent association with gender was not detected for CCRAs overall, cardiac rhythm abnormalities, and SCD prevalence, even if prevalence was higher in males than females.

CONCLUSIONS

The overall risk of occurrence of CCAs in DM1 is significantly higher in males than females regardless of genetic background and disease severity and progression. Moreover, the data also suggest a similar impact for male gender for CCRAs overall, CCAs, and SCD even if not statistically significant.

Dysphagia in adult myopathies

Dysphagia (impaired swallowing) is not a rare problem in various neuromuscular disorders, both in the pediatric and the adult patient population. On many occasions such patients are first presented to other medical specialists or health professionals. Disorders of deglutition are probably underrecognized in patients with a neuromuscular disease as a result of patient's and doctor's delay. This review will focus on dysphagia in adults suffering from a myopathy. Dysphagia in myopathies usually affects the oropharyngeal phases which rely mostly on voluntary muscle activity of the mouth, pharynx and upper esophageal sphincter. Dysphagia is known to contribute to a reduction of quality of life and may also lead to increased morbidity and mortality. The review includes an overview on symptomatology and tools of assessments, and elaborates on dysphagia in specific hereditary and acquired myopathies.

Predictors of prognosis in type 1 myotonic dystrophy (DM1): longitudinal 18-years experience from a single center

The aim of the study was to identify possible predictors of neurological worsening and need of non-invasive ventilation (NIV) in individuals affected by myotonic dystrophy type 1 (DM1), the most common form of adult-onset muscular dystrophy.

The hallmarks of myotonic dystrophy type 1 muscle dysfunction

Myotonic dystrophy type 1 (DM1) is the most prevalent form of muscular dystrophy in adults and yet there are currently no treatment options. Although this disease causes multisystemic symptoms, it is mainly characterised by myopathy or diseased muscles, which includes muscle weakness, atrophy, and myotonia, severely affecting the lives of patients worldwide. On a molecular level, DM1 is caused by an expansion of CTG repeats in the 3' untranslated region (3'UTR) of the DM1 Protein Kinase (DMPK) gene which become pathogenic when transcribed into RNA forming ribonuclear foci comprised of auto complementary CUG hairpin structures that can bind proteins. This leads to the sequestration of the muscleblind-like (MBNL) family of proteins, depleting them, and the abnormal stabilisation of CUGBP Elav-like family member 1 (CELF1), enhancing it. Traditionally, DM1 research has focused on this RNA toxicity and how it alters MBNL and CELF1 functions as key splicing regulators. However, other proteins are affected by the toxic DMPK RNA and there is strong evidence that supports various signalling cascades playing an important role in DM1 pathogenesis. Specifically, the impairment of protein kinase B (AKT) signalling in DM1 increases autophagy, apoptosis, and ubiquitin-proteasome activity, which may also be affected in DM1 by AMP-activated protein kinase (AMPK) downregulation. AKT also regulates CELF1 directly, by affecting its subcellular localisation, and indirectly as it inhibits glycogen synthase kinase 3 beta (GSK3β), which stabilises the repressive form of CELF1 in DM1. Another kinase that contributes to CELF1 mis-regulation, in this case by hyperphosphorylation, is protein kinase C (PKC). Additionally, it has been demonstrated that fibroblast growth factor-inducible 14 (Fn14) is induced in DM1 and is associated with downstream signalling through the nuclear factor κB (NFκB) pathways, associating inflammation with this disease. Furthermore, MBNL1 and CELF1 play a role in cytoplasmic processes involved in DM1 myopathy, altering proteostasis and sarcomere structure. Finally, there are many other elements that could contribute to the muscular phenotype in DM1 such as alterations to satellite cells, non-coding RNA metabolism, calcium dysregulation, and repeat-associated non-ATG (RAN) translation. This review aims to organise the currently dispersed knowledge on the different pathways affected in DM1 and discusses the unexplored connections that could potentially help in providing new therapeutic targets in DM1 research.

Antisense oligonucleotide and adjuvant exercise therapy reverse fatigue in old mice with myotonic dystrophy

Patients with myotonic dystrophy type 1 (DM1) identify chronic fatigue as the most debilitating symptom, which manifests in part as prolonged recovery after exercise. Clinical features of DM1 result from pathogenic gain-of-function activity of transcripts containing an expanded microsatellite CUG repeat (CUG^exp). In DM1 mice, therapies targeting the CUG^exp transcripts correct the molecular phenotype, reverse myotonia, and improve muscle pathology. However, the effect of targeted molecular therapies on fatigue in DM1 is unknown. Here, we use two mouse models of DM1, age-matched wild-type controls, an exercise-activity assay, electrical impedance myography, and therapeutic antisense oligonucleotides (ASOs) to show that exaggerated exercise-induced fatigue progresses with age, is unrelated to muscle fiber size, and persists despite correction of the molecular phenotype for 3 months. In old DM1 mice, ASO treatment combined with an exercise training regimen consisting of treadmill walking 30 min per day 6 days per week for 3 months reverse all measures of fatigue. Exercise training without ASO therapy improves some measures of fatigue without correction of the molecular pathology. Our results highlight a key limitation of ASO monotherapy for this clinically important feature and support the development of moderate-intensity exercise as an adjuvant for targeted molecular therapies of DM1.

Predictors of participation restriction over a 9-year period in adults with myotonic dystrophy type 1

PURPOSE

For slowly progressive neuromuscular disease, prognostic approach and long-term monitoring of participation is a crucial part of rehabilitation services. To improve the prognostic approach, professionals must identify individuals at risk of having higher participation restriction. This study aimed to identify personal and environmental predictors of participation restriction over nine years in adults with myotonic dystrophy type 1 (DM1).

METHODS

A secondary analysis of a longitudinal design comparing baseline with a follow-up nine years later was used with a multidimensional assessment of participation and personal and environmental factors. Based on theoretical models, multiple linear regressions were used.

RESULTS

One hundred and fourteen adults with DM1 were included in the study (63.2% women; 78.9% adult onset; mean (SD) age of 43.5 (10.4) years). When age, sex, phenotype, and education were controlled for, participation restriction was predicted by a longer time to stand and walk, lower grip strength, higher body mass index, absence of perceived impact of myotonia in daily living, use of adapted transportation from community services, and perception of obstacle in physical environment (p < 0.001, adjusted R² = 0.50).

CONCLUSIONS

The majority of predictors of participation restriction can be advantageously modified by rehabilitation and environmental changes, such as politics targeting community services provision or physical environment and services accessibility.Implications for rehabilitationPredictors could better inform rehabilitation professional to recognize individuals at risk of higher participation restriction over time and to target specific interventions based on a prognostic approach.Rehabilitation professionals could inform the people living with myotonic dystrophy type 1 and their relatives of the multifactorial nature of occurrence of participation restriction to diminish the "fatality" associated with a genetic progressive disorder.Predictors allow professionals to assess and intervene in the management of specific factors depending on the rehabilitation goal.Identifying individual with myotonic dystrophy with higher risk of participation restriction could help implement a long-term community based rehabilitation intervention plan targeting both personal and environmental factors.

Utility and Results from a Patient-Reported Online Survey in Myotonic Dystrophies Types 1 and 2

INTRODUCTION

Myotonic dystrophies (DMs) are the most frequent autosomal dominant neuromuscular disorders in adults. Our objective was to evaluate the utility of an online survey in a rare disease as well as to assess and compare the onset and the progression of clinical symptoms in patients with myotonic dystrophy types 1 (DM1) and 2 (DM2).

METHODS

We conducted a patient's reported online survey assessing demographics, disease-related symptoms (age of onset, first symptom, time of diagnosis, current symptoms, inheritance, and family history) combined with capturing current symptoms by validated questionnaires. The questionnaire consisted of open, closed, single- and multiple-choice questions. Multiple answers were possible in some cases. Patients with genetically confirmed DM1 or DM2 who were registered in the German DM registry or the Deutsche Gesellschaft für Muskelkranke e.V. - Diagnostic Group for DMs were invited to participate in this online survey. We calculated descriptive and exploratory analysis, where applicable.

RESULTS

Out of 677 data sets from respondents, 394 were suitable for final analysis, containing completed questionnaires from 207 DM1 (56% female) and 187 DM2 patients (71% female). The median age of onset was 28 years for DM1 and 35 years for DM2. Muscular symptoms were most frequently reported as the first symptom. The onset of myotonia was earlier than the onset of muscle weakness in both DM1 and DM2. Forty-four percent of patients with DM1 and one-third of patients with DM2 indicated muscle weakness as the first symptom. Patients with DM1 were significantly younger when experiencing muscle weakness as first symptom. Fatigue was only mentioned by a small fraction of patients as a first symptom but increased significantly in the course of the disease. There was no statistically significant difference in the incidence of cataracts, cardiac symptoms, and gastrointestinal symptoms between DM1 and DM2. Falls were reported almost equally in both groups, and most of the patients reported 2-3 falls within the past year.

DISCUSSION

Overall, as our results are consistent with the results of clinical studies and online registries, it can be assumed that this type of systematic gathering of data from patients with rare diseases is useful and provides realistic and appropriate results. Due to the nature of online surveys and the absence of an assessor, some uncertainty remains. Furthermore, survey frauds cannot be completely excluded. An additional clinical assessment could confirm the given information and will improve the utility and validity of reported symptoms participants provide in online surveys. Therefore, we recommend a combination of data collecting by online surveys and clinical assessments.

Central Nervous System Involvement as Outcome Measure for Clinical Trials Efficacy in Myotonic Dystrophy Type 1

Increasing evidences indicate that in Myotonic Dystrophy type 1 (DM1 or Steinert disease), an autosomal dominant multisystem disorder caused by a (CTG)n expansion in DMPK gene on chromosome 19q13. 3, is the most common form of inherited muscular dystrophy in adult patients with a global prevalence of 1/8000, and involvement of the central nervous system can be included within the core clinical manifestations of the disease. Variable in its severity and progression rate over time, likely due to the underlying causative molecular mechanisms; this component of the clinical picture presents with high heterogeneity involving cognitive and behavioral alterations, but also sensory-motor neural integration, and in any case, significantly contributing to the disease burden projected to either specific functional neuropsychological domains or quality of life as a whole. Principle manifestations include alterations of the frontal lobe function, which is more prominent in patients with an early onset, such as in congenital and childhood onset forms, here associated with severe intellectual disabilities, speech and language delay and reduced IQ-values, while in adult onset DM1 cognitive and neuropsychological findings are usually not so severe. Different methods to assess central nervous system involvement in DM1 have then recently been developed, these ranging from more classical psychometric and cognitive functional instruments to sophisticated psycophysic, neurophysiologic and especially computerized neuroimaging techniques, in order to better characterize this disease component, at the same time underlining the opportunity to consider it a suitable marker on which measuring putative effectiveness of therapeutic interventions. This is the reason why, as outlined in the conclusive section of this review, the Authors are lead to wonder, perhaps in a provocative and even paradoxical way to arise the question, whether or not the myologist, by now the popular figure in charge to care of a patient with the DM1, needs to remain himself a neurologist to better appreciate, evaluate and speculate on this important aspect of Steinert disease.

Myotonic dystrophy and recurrent pleomorphic adenomas: Case report and association hypothesis

We report a case of a patient with concurrent myotonic dystrophy and recurrent pleomorphic adenoma and hypothesize the association between both diseases. A 58-year-old man with classic myotonic dystrophy type 1 was diagnosed with pleomorphic adenoma. Appropriate treatment was commenced. Massive recurrences occurred within 15, 28 and 22 months respectively, after repeated surgical removal. Three case reports on similar occurrences of synchronous myotonic dystrophy and pleomorphic adenoma are discussed and an association between both disease entities is hypothesized. A conceivable association between myotonic dystrophy and pleomorphic adenoma is hypothesized by upregulation of the Wnt/Beta-catenin signaling pathway, initiated by a decreased expression of microRNA, pleomorphic adenoma gene 1 induced Beta-catenin accumulations and alterations in tumor suppressor genes and oncogenes due to RNA processing defects induced by the expanded repeat in the DMPK gene.

Cardiac involvement in inflammatory myopathies and inherited muscle diseases

PURPOSE OF REVIEW

To examine recent developments relating to cardiac involvement in the adult idiopathic inflammatory myopathies (IIM) and those inherited muscle diseases which may present in adulthood and mimic IIM.

RECENT FINDINGS

Cardiac involvement is a common feature of IIM and inherited muscle diseases. Frequency according to disease subtype varies, with serotype having particular influence in IIM, and genotype in the inherited muscle diseases. Innovative techniques for examining cardiac function have been investigated further, including speckle-tracking echocardiography and cardiac magnetic resonance tomography. The present work has highlighted a likely underestimate of the burden of cardiac disease to date. The complex relationship between IIM, atherosclerosis, and traditional cardiovascular risk factors has been further elucidated. Consensus recommendations for managing patients with inherited muscle diseases and prominent cardiac involvement have been recently published. In addition to supportive care, disease modifying treatments are increasingly becoming available for inherited muscle diseases which may also improve cardiac outcomes.

SUMMARY

Cardiac involvement is associated with significant morbidity and mortality. We suggest having a low threshold for considering the possibility of cardiac involvement in all patients with muscle disease.

Dyslexia and cognitive impairment in adult patients with myotonic dystrophy type 1: a clinical prospective analysis

BACKGROUND

Cognitive impairments in patients with myotonic dystrophy type 1 (DM1) have often been described, however, there are only few studies differentiating between partial performance disorders and mental retardation in common. This study focused on the evaluation of reading performance and the frequency of dyslexia in adult DM1 patients.

METHODS

We performed a prospective cohort study including genetically confirmed adult DM1 patients registered in the DM registry of Germany or the internal database of the Friedrich-Baur-Institute, Munich, Germany. For the assessment of the patients' reading and spelling performance, we used the standardized and validated test 'Salzburger Lese- und Rechtschreibtest' (SLRT II). The 'CFT-20 R Grundintelligenztest Skala 2' in revised ("R") version (CFT 20-R), determining the intelligence level, was appropriate to differentiate between dyslexia and general mental retardation. The diagnosis of dyslexia, the combined reading and spelling disorder, was based on the guidelines for diagnosis and therapy of children and adolescents with dyslexia 2015 (S3-guideline) providing (1) the criterion of the divergence from age level and (2) the criterion of IQ-divergence.

RESULTS

Fifty-seven DM1 patients participated in our study. Evaluating the reading performance, 16 patients fulfilled the divergence criteria of the age level and 2 patients the IQ-divergence criteria. In total, the diagnosis of a reading disorder was given in 18 DM1 patients (31.6 %). In 11 out of these 18 patients with a reading disorder, a relevant impairment of spelling performance was observed with at least three spelling errors. As there are no normative values for adults in spelling performance, we assume a combined reading disorder and dyslexia, in those 11 DM1 patients (19.3 %). Regarding the separate analyses of the test procedures, in the SLRT II the performance was below average in 40.4 % of all patients for 'word reading' and in 61.4 % of all patients for 'pseudoword reading'. There was a significant positive correlation between the CTG expansion size and a reading disorder (p=0.027). The average IQ of 17 examined DM1 patients was in the lower normal range (86.1 ± 19.1). 54.5 % of patients with reading disorder had a normal IQ.

CONCLUSION

The calculated prevalence of dyslexia in the DM1 study cohort was 19.3 % and thus considerably increased compared to the normal German population. As dyslexia is not equivalent to a general cognitive impairment, it is important not to miss dyslexic features in cognitive inconspicuous DM1 patients. Case-by-case one should consider a differential diagnostic approach, as individualized therapies can be offered to support dyslexic patients in their performance.

Characterization of individuals with selected muscular dystrophies from the expanded pilot of the Muscular Dystrophy Surveillance, Tracking and Research Network (MD STARnet) in the United States

INTRODUCTION

Data on muscular dystrophies (MDs), a heterogeneous group of heritable diseases hallmarked by progressive muscle deterioration, are scarce.

OBJECTIVE

We describe cross-sectional sociodemographic and clinical characteristics of individuals with congenital, distal, Emery-Dreifuss, facioscapulohumeral, limb-girdle, myotonic, or oculopharyngeal MD.

METHODS

The study was conducted in four sites (Arizona, Colorado, Iowa, and 12 western New York counties) as a pilot expansion of the Muscular Dystrophy Surveillance, Tracking and Research Network, funded by the Centers for Disease Control and Prevention. MDs were detected in healthcare facilities and administrative data sources using International Classification of Disease codes. Our sample contains 1,723 individuals with a MD diagnosis and a healthcare encounter between January 1, 2007 and December 31, 2011.

RESULTS AND CONCLUSIONS

Individuals were mostly non-Hispanic and white. Median ages ranged from 9.2 to 66.0 years. Most (98%) had health insurance. The proportion of individuals who were disabled or unable to work increased with age (range: 8.6-46.4%). People with limb-girdle MD aged ≥18 years were more likely to be nonambulatory (range: 24.5-44.7%). The percentages of individuals with documented clinical interventions during the surveillance period were low. The most common cause of death was respiratory causes (46.3-57.1%); an ICD-10 code for MD (G71.1 or G71.0) was reported for nearly one-half. Our findings show wide variability in sociodemographic and clinical characteristics across MDs.

Evaluating the Diagnostic and Prognostic Value of Biomarkers for Heart Disease and Major Adverse Cardiac Events in Patients With Muscular Dystrophy

AIMS

Heart disease is recognized as the leading cause of morbidity and mortality in patients with muscular dystrophy (MD). Our study demonstrates the clinical utility of cardiac biomarkers to improve the diagnosis of cardiomyopathy and prognostication of major adverse cardiac events (MACE) in these vulnerable patients.

METHODS AND RESULTS

We prospectively followed 117 patients (median age, 42 (interquartile range [IQR], 26-50) years; 49 [41.9%] women) at the Neuromuscular Multidisciplinary clinic diagnosed with a dystrophinopathy, limb-girdle MD, type 1 myotonic dystrophy, or facioscapulohumeral MD. We determined that B-type natriuretic peptide (BNP) and high-sensitive troponin I (hsTnI) were effective diagnostic markers of cardiomyopathy (area under the curve [AUC], 0.64; P=0.017; and AUC, 0.69; P=0.001, respectively). Patient risk stratification for MACE was based on cutoff values of BNP and hsTnI defined a priori as 30.5000 pg/mL and 7.6050 ng/L, respectively. Over a median follow-up period of 2.09 (IQR, 1.17-2.81) years there were 36 confirmed MACE. Multivariate regression analyses showed that patients with BNP and hsTnI levels above the respective cutoff values had a 3.70-fold (P=0.001) and 3.24-fold (P=0.002) greater risk of MACE, respectively, compared to patients with biomarker levels below. Furthermore, patients with biomarker levels above both cutoff values had a 4.08-fold (P=0.001) greater risk of MACE. Inflammatory biomarkers did not show clinical utility for heart disease in these patients.

CONCLUSION

Our study demonstrates important diagnostic and prognostic value of BNP and hsTnI as part of a comprehensive cardiac assessment to augment the management and treatment of heart disease in patients with MD.

Myotonic Muscular Dystrophies

PURPOSE OF REVIEW

This article describes the clinical features, pathogenesis, prevalence, diagnosis, and management of myotonic dystrophy type 1 and myotonic dystrophy type 2.

RECENT FINDINGS

The prevalence of myotonic dystrophy type 1 is better understood than the prevalence of myotonic dystrophy type 2, and new evidence indicates that the risk of cancer is increased in patients with the myotonic dystrophies. In addition, descriptions of the clinical symptoms and relative risks of comorbidities such as cardiac arrhythmias associated with myotonic dystrophy type 1 have been improved.

SUMMARY

Myotonic dystrophy type 1 and myotonic dystrophy type 2 are both characterized by progressive muscle weakness, early-onset cataracts, and myotonia. However, both disorders have multisystem manifestations that require a comprehensive management plan. While no disease-modifying therapies have yet been identified, advances in therapeutic development have a promising future.

Consensus-Based Care Recommendations for Pulmonologists Treating Adults with Myotonic Dystrophy Type 1

PURPOSE OF REVIEW

Myotonic dystrophy type 1 (DM1) is a severe, progressive genetic disease that affects approximately 1 in 2,500 individuals globally [Ashizawa et al.: Neurol Clin Pract 2018;8(6):507-20]. In patients with DM1, respiratory muscle weakness frequently evolves, leading to respiratory failure as the main cause of death in this patient population, followed by cardiac complications [de Die-Smulders et al.: Brain 1998;121(Pt 8):1557-63], [Mathieu et al.: Neurology 1999;52(8):1658-62], [Groh et al.: Muscle Nerve 2011;43(5):648-51]. This paper provides a more detailed outline on the diagnostic and management protocols, which can guide pulmonologists who may not have experience with DM1 or who are not part of a neuromuscular multidisciplinary clinic. A group of neuromuscular experts in DM1 including pulmonologists, respiratory physiotherapists and sleep specialists discussed respiratory testing and management at baseline and during follow-up visits, based on their clinical experience with patients with DM1. The details are presented in this report.

RECENT FINDINGS

Myotonic recruited 66 international clinicians experienced in the treatment of people living with DM1 to develop and publish consensus-based care recommendations targeting all body systems affected by this disease [Ashizawa et al.: Neurol Clin Pract. 2018;8(6):507-20]. Myotonic then worked with 12 international respiratory therapists, pulmonologists and neurologists with long-standing experience in DM respiratory care to develop consensus-based care recommendations for pulmonologists using a methodology called the Single Text Procedure. This process generated a 7-page document that provides detailed respiratory care recommendations for the management of patients living with DM1. This consensus is completely based on expert opinion and not backed up by empirical evidence due to limited clinical care data available for respiratory care management in DM patients. Nevertheless, we believe it is of relevance for professionals treating adults with myotonic dystrophy because it addresses practical issues related to respiratory management and care, which have been adapted to meet the specific issues in patients with DM1.

SUMMARY

The resulting recommendations are intended to improve respiratory care for the most vulnerable of DM1 patients and lower the risk of untoward respiratory complications and mortality by providing pulmonologist who are less experienced with DM1 with practical indications on which tests and when to perform them, adapting the general respiratory knowledge to specific issues related to this multiorgan disease.

[Study of medical practices for patients with myotonic dystrophy in Japan-Nationwide specialist survey]

To reveal current status of medical practice, we made a nationwide self-questionnaire survey to Japanese certified Neurologists and Child Neurologists. Most specialists seeing patients with myotonic dystrophy (DM) were aware that genetic analysis is approved in health insurance. The ratio of pre-explanation about genetic analysis was also high however written informed consent was not always obtained. Over 60% of specialists regarded motor dysfunction, conduction block/arrhythmia, heart failure, dysphagia, hypoventilation as important complications, while no more than 35% of specialists regarded hypoxia/apnea, multi-organ complications, which are feature of myotonic dystrophy, as important. Over half specialists did not check Holter electrocardiogram, sleep respiratory examination, or swallowing function regularly. This fact implied that cumbersome examinations tended to be refrained from regular assessment. Child neurologists were more aggressive in respiratory care and consultation of cardiovascular specialists. A few neurologists hesitated to introduce mechanical ventilation and tube feeding.

Clinical Care Recommendations for Cardiologists Treating Adults With Myotonic Dystrophy

Myotonic dystrophy is an inherited systemic disorder affecting skeletal muscle and the heart. Genetic testing for myotonic dystrophy is diagnostic and identifies those at risk for cardiac complications. The 2 major genetic forms of myotonic dystrophy, type 1 and type 2, differ in genetic etiology yet share clinical features. The cardiac management of myotonic dystrophy should include surveillance for arrhythmias and left ventricular dysfunction, both of which occur in progressive manner and contribute to morbidity and mortality. To promote the development of care guidelines for myotonic dystrophy, the Myotonic Foundation solicited the input of care experts and organized the drafting of these recommendations. As a rare disorder, large scale clinical trial data to guide the management of myotonic dystrophy are largely lacking. The following recommendations represent expert consensus opinion from those with experience in the management of myotonic dystrophy, in part supported by literature-based evidence where available.

Patient Input to Inform the Development of Central Nervous System Outcome Measures in Myotonic Dystrophy

Myotonic dystrophy type 1 (DM1) and myotonic dystrophy type 2 (DM2) are multisystem, genetic disorders caused by repeat expansions on chromosome 19 (DM1) and chromosome 3 (DM2). Although the effects of DM on the skeletal, cardiac, and smooth muscles, as well as the endocrine and central nervous systems, can be disabling, there are no disease-modifying therapies for the disorder. Following a process established by the US Food and Drug Administration (FDA) in 2012 known as the Patient-Focused Drug Development (PFDD) Initiative, Myotonic (formerly the Myotonic Dystrophy Foundation) has been conducting patient- and caregiver-inclusive sessions to explore disease burden as defined by patients and caregivers, and what affected individuals want most from potential new therapies. In September 2017, at Myotonic’s annual conference, a session titled “Bringing the Patient Voice to CNS-Targeting Drug Development in Myotonic Dystrophy” attracted some 350 members of the DM community. During the session, patients and caregivers described CNS disease symptoms, their impact on quality of life, and potential CNS-related targets that they considered important for drug development consideration. These included fatigue and daytime sleepiness; dysregulated sleep; cognitive deficits such as “brain fog,” memory and focus impairment, learning and attention difficulties, and time management challenges; emotional/psychological/behavioral difficulties, including impulsivity, apathy, antisocial behavior, personality changes, and depression; social difficulties, including disconnection, lack of awareness, and feelings of isolation; and general anxieties about the future and potential loss of independence. Improvements in memory and lessening of “brain fog” were considered particularly important.

Clinical and genetic characteristics of childhood-onset myotonic dystrophy

INTRODUCTION

Myotonic dystrophy type 1 (DM1) is caused by a CTG (cytosine-thymine-guanine) trinucleotide repeat expansion. Congenital DM (CDM) presents in the first month of life, whereas individuals with infantile and juvenile DM1 have later onset of symptoms.

METHODS

We performed a retrospective chart review of patients with childhood-onset DM1 seen at one of three locations in Dallas, Texas between 1990 and 2018. Symptoms, disease course, cognitive features, and family history were reviewed.

RESULTS

Seventy-four patients were included; CDM was diagnosed in 52 patients. There was maternal inheritance in 74% of patients. CTG repeat number ranged from 143 to 2300. Neuropsychiatric and cognitive deficits were common. Over half of the patients had GI disturbances, and orthopedic complications were common.

DISCUSSION

Myotonic dystrophy type 1 in children requires a multidisciplinary approach to management. Presenting symptoms vary, and repeat expansion size does not necessarily directly relate to severity of symptoms. A consensus for outcome measures is required.

Family communication following a diagnosis of myotonic dystrophy: To tell or not to tell?

Family communication about genetic information enables informed medical and reproductive decision-making. The literature suggests that a significant proportion of genetically at-risk family members remain uninformed about genetic risk information as a result of non-disclosure. This study explored the experiences of New Zealand families communicating about a diagnosis of type 1 myotonic dystrophy (DM1). Eligible individuals were identified and recruited from the New Zealand (NZ) MD Prev study, a nationwide study which aimed to determine the prevalence, impact, and costs of genetic muscle disorders across the lifespan. Twelve qualitative semi-structured interviews were conducted with 17 participants. The findings demonstrate diversity among and within families, with several distinct family narratives described. Most participants reported a motivation to tell relatives about their diagnosis to promote autonomy. Women were pivotal throughout communication processes and this was often tied to the concept of maternal responsibility and a desire to promote relatives' reproductive autonomy. The diagnosis of DM1 and the subsequent family communication decisions altered relationships for many, with both positive and negative impacts described. The findings demonstrate that individuals require time to explore the impact of a diagnosis of DM1 on self, family and intimate partner relationships to anticipate unique communication challenges. Genetic counselors can use these findings to inform their approach to counseling families with DM1. Longitudinal genetic counseling may be beneficial as a way to provide individuals with life stage specific support as they communicate with their relatives about a diagnosis of DM1.

CRISPR/Cas Applications in Myotonic Dystrophy: Expanding Opportunities

CRISPR/Cas technology holds promise for the development of therapies to treat inherited diseases. Myotonic dystrophy type 1 (DM1) is a severe neuromuscular disorder with a variable multisystemic character for which no cure is yet available. Here, we review CRISPR/Cas-mediated approaches that target the unstable (CTG•CAG)n repeat in the DMPK/DM1-AS gene pair, the autosomal dominant mutation that causes DM1. Expansion of the repeat results in a complex constellation of toxicity at the DNA level, an altered transcriptome and a disturbed proteome. To restore cellular homeostasis and ameliorate DM1 disease symptoms, CRISPR/Cas approaches were directed at the causative mutation in the DNA and the RNA. Specifically, the triplet repeat has been excised from the genome by several laboratories via dual CRISPR/Cas9 cleavage, while one group prevented transcription of the (CTG)n repeat through homology-directed insertion of a polyadenylation signal in DMPK. Independently, catalytically deficient Cas9 (dCas9) was recruited to the (CTG)n repeat to block progression of RNA polymerase II and a dCas9-RNase fusion was shown to degrade expanded (CUG)n RNA. We compare these promising developments in DM1 with those in other microsatellite instability diseases. Finally, we look at hurdles that must be taken to make CRISPR/Cas-mediated editing a therapeutic reality in patients.

Interprofessional Care for Neuromuscular Disease

PURPOSE OF REVIEW

This review aims to delineate interprofessional care models for neuromuscular disease. Evidence regarding both the benefits and barriers to interprofessional neuromuscular care in both inpatient and outpatient settings is presented. Finally, opportunities to improve both access to and quality of care provided by interprofessional team clinics will be discussed.

RECENT FINDINGS

Although the term "multidisciplinary" is often misapplied to denote any interprofessional team-based care setting, there are important differences in team structure and dynamics in each of the three most common models: multidisciplinary, interdisciplinary, and transdisciplinary care. Evidence favors the more integrated interdisciplinary and transdisciplinary models for better patient outcomes and decreased staff burnout. Coordinated interprofessional care results in improved health outcomes, resource utilization, and patient satisfaction for persons with adult and pediatric neuromuscular disease. Distance remains the greatest barrier to specialized team-based care for this population; telehealth technologies may make interprofessional care more accessible to these persons. Despite limited evidence for the broader population of persons with neuromuscular disease, consensus guidelines increasingly support this model of care delivery. Further work may help determine effectiveness for other populations of persons with neuromuscular disease and best practices within these team-based models of care.

The DM-scope registry: a rare disease innovative framework bridging the gap between research and medical care

BACKGROUND

The relevance of registries as a key component for developing clinical research for rare diseases (RD) and improving patient care has been acknowledged by most stakeholders. As recent studies pointed to several limitations of RD registries our challenge was (1) to improve standardization and data comparability; (2) to facilitate interoperability between existing RD registries; (3) to limit the amount of incomplete data; (4) to improve data quality. This report describes the innovative concept of the DM-Scope Registry that was developed to achieve these objectives for Myotonic Dystrophy (DM), a prototypical example of highly heterogeneous RD. By the setting up of an integrated platform attractive for practitioners use, we aimed to promote DM epidemiology, clinical research and patients care management simultaneously.

RESULTS

The DM-Scope Registry is a result of the collaboration within the French excellence network established by the National plan for RDs. Inclusion criteria is all genetically confirmed DM individuals, independently of disease age of onset. The dataset includes social-demographic data, clinical features, genotype, and biomaterial data, and is adjustable for clinical trial data collection. To date, the registry has a nationwide coverage, composed of 55 neuromuscular centres, encompassing the whole disease clinical and genetic spectrum. This widely used platform gathers almost 3000 DM patients (DM1 n = 2828, DM2 n = 142), both children (n = 322) and adults (n = 2648), which accounts for > 20% of overall registered DM patients internationally. The registry supported 10 research studies of various type i.e. observational, basic science studies and patient recruitment for clinical trials.

CONCLUSION

The DM-Scope registry represents the largest collection of standardized data for the DM population. Our concept improved collaboration among health care professionals by providing annual follow-up of quality longitudinal data collection. The combination of clinical features and biomolecular materials provides a comprehensive view of the disease in a given population. DM-Scope registry proves to be a powerful device for promoting both research and medical care that is suitable to other countries. In the context of emerging therapies, such integrated platform contributes to the standardisation of international DM research and for the design of multicentre clinical trials. Finally, this valuable model is applicable to other RDs.

Uncovering health and social care needs among myotonic dystrophy patients: Utility of the Needs and Provisions Complexity Scale

OBJECTIVES

Myotonic dystrophy type 1 (DM1) is a slowly progressive multisystem disorder. Guidelines recommend multidisciplinary follow-up. We aimed to investigate the presence of unmet health and social care needs among patients with DM1 and whether unmet needs correlated with motor function, cognitive impairments, or quality of life.

MATERIAL AND METHODS

Patients were 22 adults with DM1. "Needs and Provisions Complexity Scale" (NPCS) was applied to evaluate the individual's needs and provision of health and social services. The Muscular Impairment Rating Scale (MIRS) was used to measure motor function and disease stage. All patients underwent neuropsychological testing. The EQ-5D-3L questionnaire was used to evaluate the patients' health-related quality of life (HRQoL).

RESULTS

Median time from diagnosis was 11 years (range: 1-40). Twenty patients had developed needs related to social care, personal care, and rehabilitation that had not been met, whereas need for medical follow-up was largely met. The more pronounced the muscular impairment, the more unmet needs were experienced by DM1 patients (r = 0.50, P = 0.019). Degree of unmet needs did not correlate with full-scale IQ (r = -0.27, P = 0.23) or HRQoL (r = -0.14, P = 0.55).

CONCLUSION

Using NPCS, we discovered that patients with DM1 had unmet needs with respect to social care, personal care, and rehabilitation although their need for medical follow-up was met. Thus, the use of NPCS helped bring our practice in better accordance with guidelines. A higher MIRS grade should alert the clinician to the likelihood of unmet needs.

A Case Report of Myotonic Disease and Gastric Bypass and a Literature Review

We report the case of a woman with myotonic dystrophy type 1, followed for 8 years after a Roux-en-Y gastric bypass. Weigh loss was substantial (53% of initial body weight) with functional improvement in spite of the natural course of the pathology. Five other cases have been published and have reported a relatively positive benefit/risk ratio. Precautions are to be taken at the time of anesthesia and follow-up in order to detect possible degradation of muscle function.

Consensus-based care recommendations for adults with myotonic dystrophy type 2

Purpose of review

Myotonic dystrophy type 2 (DM2) is a rare, progressive multisystem disease particularly affecting the skeletal muscle. A causal therapy is not yet available; however, prompt, appropriate symptomatic treatments are essential to limit disease-related complications. Evidence-based guidelines to assist medical practitioners in the care of DM2 patients do not exist.

Recent findings

The Myotonic Dystrophy Foundation (MDF) previously worked with an international group of 66 clinicians to develop consensus-based care recommendations for myotonic dystrophy type 1. Following a similar approach, the MDF recruited 15 international clinicians with long-standing experience in the care of DM2 patients to develop consensus-based care recommendations. The single text procedure was adopted. This process generated a 4-page Quick Reference Guide and a comprehensive 55-page document that provides care recommendations for DM2 patients.

Summary

The resulting recommendations will help standardize and improve care for DM2 patients and facilitate appropriate management in centers without neuromuscular specialists.

Sugammadex is changing the paradigm in neuromuscular blockade in patients with myotonic dystrophy

Myotonic dystrophy type 1 is a rare neuromuscular disease that represents a challenge to anaesthetic management. Most of the literature does not recommend the usage of neuromuscular blocking agents, if general anaesthesia is needed in these patients. Depolarising neuromuscular blocking agents like suxamethonium are contraindicated, and there might be an increased sensitivity to non-depolarising agents like rocuronium with greater risk of postoperative residual neuromuscular blockade and consequent respiratory failure. Reversing neuromuscular blockade is also problematic as neostigmine can induce myotonic crisis, impairing normal ventilation. We discuss the use of sugammadex for neuromuscular blockade reversal, from a clinical case of a patient with myotonic dystrophy type 1 for laparoscopic cholecystectomy. The patient had a general anaesthesia with neuromuscular blockade with rocuronium. After the surgical procedure, neuromuscular blockade was safely reversed with sugammadex, guided by neuromuscular monitoring without any perioperative complications.