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Background: LAMA2-related muscular dystrophy (LAMA2-RD) encompasses a group of recessive muscular dystrophies caused by mutations in the LAMA2 gene, which codes for the alpha-2 chain of laminin-211 (merosin). Diagnosis is straightforward in the classic congenital presentation with no ambulation and complete merosin deficiency in muscle biopsy, but is far more difficult in milder ambulant individuals with partial merosin deficiency. Objective: To investigate the diagnostic utility of muscle imaging in LAMA2-RD using whole-body magnetic resonance imaging (WBMRI). Results: 27 patients (2–62 years, 21–80% with acquisition of walking ability and 6 never ambulant) were included in an international collaborative study. All carried two pathogenic mutations, mostly private missense changes. An intronic variant (c.909 + 7A > G) was identified in all the Chilean cases. Three patients (two ambulant) showed intellectual disability, epilepsy, and brain structural abnormalities. WBMRI T1w sequences or T2 fat-saturated images (Dixon) revealed abnormal muscle fat replacement predominantly in subscapularis, lumbar paraspinals, gluteus minimus and medius, posterior thigh (adductor magnus, biceps femoris, hamstrings) and soleus. This involvement pattern was consistent for both ambulant and non-ambulant patients. The degree of replacement was predominantly correlated to the disease duration, rather than to the onset or the clinical severity. A "COL6-like sandwich sign" was observed in several muscles in ambulant adults, but different involvement of subscapularis, gluteus minimus, and medius changes allowed distinguishing LAMA2-RD from collagenopathies. The thigh muscles seem to be the best ones to assess disease progression. Conclusion: WBMRI in LAMA2-RD shows a homogeneous pattern of brain and muscle imaging, representing a supportive diagnostic tool. [ABSTRACT FROM AUTHOR]

Introduction: With the advent of emerging molecular therapies for muscular dystrophies, the need for knowledge about natural history course of such diseases is of utmost importance in the preparation for future trials. However, for Becker muscular dystrophy such knowledge is scarce. Objective: In this 1-year follow-up study, we examined disease progression in Becker muscular dystrophy by monitoring changes in MRI-assessed muscle fat fraction (FF) in axial and lower limb muscles and quantitative muscle strength of axial muscles. Methods and Materials: Sixteen patients with Becker muscular dystrophy were investigated by (1) muscle strength of the trunk using a Biodex dynamometer and (2) Dixon muscle MRI of paraspinal and lower limb muscles. Quantitative MRI data was analyzed in two parts: The first part consisted of all participants (N = 16). The second analysis assessed two separate groups comprising lesser affected participants (N = 5) and more severely affected patients (n = 11). Results: Trunk extension and flexion strength remained stable from baseline to follow-up. MRI did not show any significant increase in muscle FF % from baseline to follow-up in all patients, except for multifidus at the spinal level T12 (p = 0.01). However, when we analyzed the two subgroups, according to disease severity, FF% increased in the lesser severely affected group at L4/L5 erector spinae (p = 0.047), sartorius (p = 0.028), gracilis (p = 0.009), tibialis anterior (p = 0.047), peroneals (p = 0.028), and gastrocnemius medialis (p = 0.009), while the severely affected group only increased significantly at T12 multifidus (p = 0.028) and T12 erector spinae (p = 0.011). No difference in muscle strength was observed in the two subgroups. Conclusion: Our results add to the existing knowledge about the natural rate of disease progression in BMD. As quantitative MRI was able to identify changes where strength assessment was not, MRI could be a strong biomarker for change in BMD. However, our findings show that it is important to stratify patients with BMD according to phenotype for future clinical trials. [ABSTRACT FROM AUTHOR]

Using MRI, the main aim was to (1) map the pattern of muscle involvement by assessing fat fraction and (2) investigate frequency of target and sandwich signs in 42 muscles of patients with Bethlem myopathy (BM). Fifteen BM patients were included. Results were compared to findings in 8 healthy controls and 50 patients with four other types of muscular dystrophies. All muscles, except one, showed higher fat fraction in BM patients vs healthy controls (p < 0.05) with an overall proximal muscle affection, resembling a limb girdle-like pattern. In moderate patients, the specificity was 90% for the sandwich sign and 98% for the target sign. Sensitivity for both signs was 100%. Twelve BM patients had sandwich sign in other muscles than the vastus lateralis. Muscle strength correlated with fat fraction. Mean fat fraction in the psoas major was 39% in BM patients, which was considerably higher than in 3 of the 4 muscular dystrophy control diseases. The presence of signs in conjunction with severe affection of the psoas major muscle can serve as a diagnostic tool in BM. The high level of STIR lesions in muscles of BM patients warrants further investigations. [ABSTRACT FROM AUTHOR]

Objective: The Global FKRP Registry is a database for individuals with conditions caused by mutations in the Fukutin‐Related Protein (FKRP) gene: limb girdle muscular dystrophy R9 (LGMDR9, formerly LGMD2I) and congenital muscular dystrophies MDC1C, Muscle–Eye–Brain Disease and Walker–Warburg Syndrome. The registry seeks to further understand the natural history and prevalence of FKRP‐related conditions; aid the rapid identification of eligible patients for clinical studies; and provide a source of information to clinical and academic communities. Methods: Registration is patient‐initiated through a secure online portal. Data, reported by both patients and their clinicians, include: age of onset, presenting symptoms, family history, motor function and muscle strength, respiratory and cardiac function, medication, quality of life and pain. Results: Of 663 registered participants, 305 were genetically confirmed LGMDR9 patients from 23 countries. A majority of LGMDR9 patients carried the common mutation c.826C > A on one or both alleles; 67.9% were homozygous and 28.5% were compound heterozygous for this mutation. The mean ages of symptom onset and disease diagnosis were higher in individuals homozygous for c.826C > A compared with individuals heterozygous for c.826C > A. This divergence was replicated in ages of loss of running ability, wheelchair‐dependence and ventilation assistance; consistent with the milder phenotype associated with individuals homozygous for c.826C > A. In LGMDR9 patients, 75.1% were currently ambulant and 24.6%, nonambulant (unreported in 0.3%). Cardiac impairment was reported in 23.2% (30/129). Interpretation: The Global FKRP Registry enables the collection of patient natural history data, which informs academics, healthcare professionals and industry. It represents a trial‐ready cohort of individuals and is centrally placed to facilitate recruitment to clinical studies. [ABSTRACT FROM AUTHOR]

Objective: The Popeye domain containing 3 (POPDC3) gene encodes a membrane protein involved in cyclic adenosine monophosphate (cAMP) signaling. Besides gastric cancer, no disease association has been described. We describe a new muscular dystrophy associated with this gene.Methods: We screened 1,500 patients with unclassified limb girdle weakness or hyperCKemia for pathogenic POPDC3 variants. Five patients carrying POPDC3 variants were examined by muscle magnetic resonance imaging (MRI), muscle biopsy, and cardiac examination. We performed functional analyses in a zebrafish popdc3 knockdown model and heterologous expression of the mutant proteins in Xenopus laevis oocytes to measure TREK-1 current.Results: We identified homozygous POPDC3 missense variants (p.Leu155His, p.Leu217Phe, and p.Arg261Gln) in 5 patients from 3 ethnically distinct families. Variants affected highly conserved residues in the Popeye (p.Leu155 and p.Leu217) and carboxy-terminal (p.Arg261) domains. The variants were almost absent from control populations. Probands' muscle biopsies were dystrophic, and serum creatine kinase levels were 1,050 to 9,200U/l. Muscle weakness was proximal with adulthood onset in most patients and affected lower earlier than upper limbs. Muscle MRI revealed fat replacement of paraspinal and proximal leg muscles; cardiac investigations were unremarkable. Knockdown of popdc3 in zebrafish, using 2 different splice-site blocking morpholinos, resulted in larvae with tail curling and dystrophic muscle features. All 3 mutants cloned in Xenopus oocytes caused an aberrant modulation of the mechano-gated potassium channel, TREK-1.Interpretation: Our findings point to an important role of POPDC3 for skeletal muscle function and suggest that pathogenic variants in POPDC3 are responsible for a novel type of autosomal recessive limb girdle muscular dystrophy. ANN NEUROL 2019;86:832-843. [ABSTRACT FROM AUTHOR]

Background and Objective: Oculopharyngeal muscular dystrophy (OPMD) is a genetic disorder caused by an abnormal expansion of GCN triplets within the PABPN1 gene. Previous descriptions have focused on lower limb muscles in small cohorts of patients with OPMD, but larger imaging studies have not been performed. Previous imaging studies have been too small to be able to correlate imaging findings to genetic and clinical data.Methods: We present cross-sectional, T1-weighted muscle MRI and CT-scan data from 168 patients with genetically confirmed OPMD. We have analysed the pattern of muscle involvement in the disease using hierarchical analysis and presented it as heatmaps. Results of the scans were correlated with genetic and clinical data.Results: Fatty replacement was identified in 96.7% of all symptomatic patients. The tongue, the adductor magnus and the soleus were the most commonly affected muscles. Muscle pathology on MRI correlated positively with disease duration and functional impairment.Conclusions: We have described a pattern that can be considered characteristic of OPMD. An early combination of fat replacement in the tongue, adductor magnus and soleus can be helpful for differential diagnosis. The findings suggest the natural history of the disease from a radiological point of view. The information generated by this study is of high diagnostic value and important for clinical trial development. [ABSTRACT FROM AUTHOR]

Increasing evidence suggests that high-intensity training (HIT) is a time-efficient exercise strategy to improve fitness. HIT has never been explored in neuromuscular diseases, likely because it may seem counterintuitive. A single session of high-intensity exercise has been studied without signs of muscle damage in facioscapulohumeral muscular dystrophy type 1 (FSHD1). We aimed to determine whether HIT is safe and effective in FSHD1 in a randomized, controlled parallel study. Untrained adults with genetically verified FSHD1 ( n = 13) able to perform cycle-ergometer exercise were randomized to 8 weeks of supervised HIT ( n = 6) (3 × 10-min cycle-ergometer-HIT/week) or 8 weeks of usual care ( n = 7). Following this, all participants performed 8 weeks of unsupervised HIT (3 × 10-min cycle-ergometer-HIT/week). Primary outcome was fitness, maximal oxygen uptake/min/kg body weight. Furthermore, workload, 6-min walk distance, 5-time sit-to-stand time, muscle strength, and daily activity levels were measured. Pain, fatigue, and plasma-CK were monitored. Twelve patients completed the randomized part of the study. Plasma-CK levels and pain scores were unaffected by HIT. Supervised HIT improved fitness (3.3 ml O/min/kg, CI 1.2-5.5, P < 0.01, n = 6, NNT = 1.4). Unsupervised HIT also improved fitness (2.0 ml O/min/kg, CI 0.1-3.9, P = 0.04, n = 4). There was no training effect on other outcomes. Patients preferred HIT over strength and moderate-intensity aerobic training. It may seem counterintuitive to perform HIT in muscular dystrophies, but this RCT shows that regular HIT is safe, efficacious, and well liked by moderately affected patients with FSHD1, which suggests that HIT is a feasible method for rehabilitating patients with FSHD1. [ABSTRACT FROM AUTHOR]

Classically, myopathies are categorized according to limb or cranial nerve muscle affection, but with the growing use of magnetic resonance imaging it has become evident that many well-known myopathies have significant involvement of the axial musculature. New disease entities with selective axial muscle involvement have also been described recently, but overall the axial myopathy is unexplored. We performed a PubMed search using the search terms 'myopathy', 'paraspinal', 'axial' and 'erector'. Axial myopathy was defined as involvement of paraspinal musculature. We found evidence of axial musculature involvement in the majority of myopathies in which paraspinal musculature was examined. Even in diseases named after a certain pattern of non-axial muscle affection, such as facioscapulohumeral and limb girdle muscular dystrophies, affection of the axial musculature was often severe and early, compared to other muscle groups. Very sparse literature evaluating the validity of clinical assessment methods, electromyography, muscle biopsy and magnetic resonance imaging was identified and reference material is generally missing. This article provides an overview of the present knowledge on axial myopathy with the aim to increase awareness and spur interest among clinicians and researchers in the field. [ABSTRACT FROM AUTHOR]

Objective: The 6-minute walk test is widely used to assess functional status in neurological disorders. However, the test is subject to great inter-test variability due to fluctuating motivation, fatigue and learning effects. We investigated whether inter-test variability of the 6MWT can be reduced by heart rate correction. Methods: Sixteen patients with neuromuscular diseases, including Facioscapulohumeral muscular dystrophy, Limb-girdle muscular dystrophy, Charcot-Marie-Tooths, Dystrophia Myotonica and Congenital Myopathy and 12 healthy subjects were studied. Patients were excluded if they had cardiac arrhythmias, if they received drug treatment for hypertension or any other medical conditions that could interfere with the interpretation of the heart rate and walking capability. All completed three 6-minute walk tests on three different test-days. Heart rate was measured continuously. Results: Successive standard 6-minute walk tests showed considerable learning effects between Tests 1 and 2 (4.9%; P = 0.026), and Tests 2 and 3 (4.5%; P = 0.020) in patients. The same was seen in controls between Tests 1 and 2 (8.1%; P = 0.039)). Heart rate correction abolished this learning effect. Conclusion: A modified 6-minute walk test, by correcting walking distance with average heart rate during walking, decreases the variability among repeated 6-minute walk tests, and should be considered as an alternative outcome measure to the standard 6-minute walk test in future clinical follow-up and treatment trials. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction We investigated the effect of high-intensity exercise on plasma creatine kinase (CK) in patients with muscular dystrophies. Methods Fourteen patients with Becker (BMD), facioscapulohumeral (FSHD), or limb-girdle type 2 (LGMD2) muscular dystrophy, and 8 healthy subjects performed 5 cycling tests: an incremental max test, and tests at 65%, 75%, 85%, and 95% of maximal oxygen uptake (VO2max). Heart rate and oxygen consumption were measured during the tests, and plasma CK was measured before, immediately after, and 24 hours after exercise. Results All subjects were able to perform high-intensity exercise at the different levels. In patients with LGMD2 and FSHD, CK normalized 24 hours after exercise compared with the pre-exercise value, whereas those with BMD and healthy controls had elevated CK values 24 hours after exercise. Conclusions The findings suggest that high-intensity exercise is generally well tolerated in patients with LGMD2 and FSHD, whereas those with BMD may be more prone to exercise-induced damage. Muscle Nerve 48: 897-901, 2013 [ABSTRACT FROM AUTHOR]

• Muscle imaging can provide different biomarkers for FSHD. • Consensus on the diagnostic usefulness of MRI and its role in patients' stratification. • Consensus on the harmonization and improvement of available quantitative MRI protocols. • Proposal of a shared research agenda between the FSHD CTRN and ETN imaging working groups. [ABSTRACT FROM AUTHOR]

We investigated if Growth and Differentiation Factor 15 (GDF-15) can be used as a biomarker to distinguish patients with mitochondrial myopathy from patients with other myopathies. Serum GDF-15 was measured in 28 patients with mitochondrial disease, 24 with metabolic myopathies, 27 with muscular dystrophy and 21 healthy controls. Our findings indicate that elevated GDF-15 can distinguish patients with mitochondrial myopathy from other myopathies, including metabolic myopathies. This suggests that increases in GDF-15 is specific to respiratory chain dysfunction rather than general metabolic dysfunction or muscle defect. [ABSTRACT FROM AUTHOR]

• Whole body MRI (WBMRI) is an important imaging biomarker for myopathies. • Different mutations within the same gene can have different clinical WBMRI patterns. • WBMRI assesses all muscles in face, limbs and trunk not imaged in standard protocols. • MRI sequences measure atrophy / fatty infiltration (T1) and edema (T2 or STIR, IDEAL T2). • 3-point Dixon sequences provide better quantification of muscle water and fat content. Whole-body magnetic resonance imaging has emerged as a useful imaging tool in diagnosing and characterizing the progression of myopathies and muscular dystrophies. Whole-body MRI indications and diagnostic efficacy are becoming better defined with the increasing number of cases, publications and discussions within multidisciplinary working groups. Advanced Whole-body MRI protocols are rapid, lower cost, and well-tolerated by patients. Accurate interpretation of muscle Whole-body MRI requires a detailed knowledge of muscle anatomy and differential pattern of involvement in muscle diseases. With the surge in recently identified novel genetic myopathies, Whole-body MRI will become increasingly useful for phenotypic validation of genetic variants of unknown significance. In addition, Whole-body MRI will be progressively used as a biomarker for disease progression and quantify response to therapy with the emergence of novel disease modifying treatments. This review outlines Whole-body MRI indications and updates refined protocols and provides a comprehensive overview of the diagnostic utility and suggested methodology of Whole-body MRI for pediatric and adult patients with muscle diseases. [ABSTRACT FROM AUTHOR]