Functional impairments, fatigue and quality of life in RYR1-related myopathies: A questionnaire study.

Mutations in RYR1 are a common genetic cause of non-dystrophic neuromuscular disorders. To obtain baseline data concerning the prevalence of fatigue, the psychological disease burden and quality of life associated with these common conditions, we performed a questionnaire study. Seventy-two patients were included in this study, 33 with a congenital myopathy and 39 with malignant hyperthermia or exertional rhabdomyolysis. Our results showed that patients with RYR1-related myopathies have more functional impairments and significant chronic fatigue compared to healthy controls, with almost half of patients being severely fatigued. Whilst fatigue, pain and associated physical and social difficulties were more pronounced in those with permanent phenotypes, individuals with intermittent phenotypes also scored higher in all relevant categories compared to healthy controls. These findings indicate that RYR1-related myopathies, despite being often considered relatively mild conditions, are nevertheless associated with severe fatigue and functional limitations, resulting in substantial loss of quality of life. Moreover, milder but in essence similar findings in patients with RYR1-related malignant hyperthermia and rhabdomyolysis suggest that those phenotypes are not truly episodic but in fact associated with a substantial permanent disease burden. These preliminary data should help to design more comprehensive quality of life studies to inform standards of care.

Involvement of pelvic girdle and proximal leg muscles in early oculopharyngeal muscular dystrophy.

Although limb girdle weakness is not part of the major diagnostic criteria of oculopharyngeal muscular dystrophy (OPMD), it has frequently been observed in the Dutch and other OPMD cohorts. In the Dutch cohort, this might be related to the relatively old age or the severity of the genetic defect. This patient-control study (14 OPMD patients and 12 controls) investigated the involvement of limb girdle muscles with a multidimensional approach in early OPMD. We assessed functional abilities, disease impact, physical activity, muscle strength, histopathology and fatty infiltration using questionnaires, actometer, functional tests, manual and quantitative muscle testing, muscle biopsy and muscle MRI. The study showed that involvement of pelvic girdle and proximal leg can be a relatively early feature of OPMD, resulting in impaired daily life activities. The fat fraction of the hip adductors and hamstrings was significantly higher in OPMD patients than in controls. Future studies should include assessment of hip flexors, hip adductors and hamstrings (muscle strength measurements and MRI), functional tests and questionnaires. These findings are important in future diagnostics, management and for the design of outcome measures in trials.

Cytosolic 5'-nucleotidase 1A autoantibody profile and clinical characteristics in inclusion body myositis.

OBJECTIVES: Autoantibodies directed against cytosolic 5'-nucleotidase 1A have been identified in many patients with inclusion body myositis. This retrospective study investigated the association between anticytosolic 5'-nucleotidase 1A antibody status and clinical, serological and histopathological features to explore the utility of this antibody to identify inclusion body myositis subgroups and to predict prognosis. MATERIALS AND METHODS: Data from various European inclusion body myositis registries were pooled. Anticytosolic 5'-nucleotidase 1A status was determined by an established ELISA technique. Cases were stratified according to antibody status and comparisons made. Survival and mobility aid requirement analyses were performed using Kaplan-Meier curves and Cox proportional hazards regression. RESULTS: Data from 311 patients were available for analysis; 102 (33%) had anticytosolic 5'-nucleotidase 1A antibodies. Antibody-positive patients had a higher adjusted mortality risk (HR 1.89, 95% CI 1.11 to 3.21, p=0.019), lower frequency of proximal upper limb weakness at disease onset (8% vs 23%, adjusted OR 0.29, 95% CI 0.12 to 0.68, p=0.005) and an increased prevalence of excess of cytochrome oxidase deficient fibres on muscle biopsy analysis (87% vs 72%, adjusted OR 2.80, 95% CI 1.17 to 6.66, p=0.020), compared with antibody-negative patients. INTERPRETATION: Differences were observed in clinical and histopathological features between anticytosolic 5'-nucleotidase 1A antibody positive and negative patients with inclusion body myositis, and antibody-positive patients had a higher adjusted mortality risk. Stratification of inclusion body myositis by anticytosolic 5'-nucleotidase 1A antibody status may be useful, potentially highlighting a distinct inclusion body myositis subtype with a more severe phenotype.

The yield of diagnostic work-up of patients presenting with myalgia, exercise intolerance, or fatigue: A prospective observational study.

Myalgia, fatigue, and exercise intolerance are cause for referral to a neurologist. However, the diagnostic value of history, neurological examination, and ancillary investigations in patients with these symptoms is unknown. This study provides a sound footing for deciding which ancillary investigations should be conducted. A prospective observational study of the diagnostic approach in 187 patients with myalgia, exercise intolerance, or fatigue as their predominant symptom was performed. The primary outcomes were independent contribution of referral letter, history, examination, and ancillary investigations to a myopathy diagnosis. The secondary outcome was diagnostic value of combined ancillary investigations. 27% of patients had a myopathy. Positive family history (OR 3.2), progressive symptoms (OR 2.2), atrophy (OR 9.7), weakness (OR 10.9), and hyporeflexia (OR 4.4) were associated with a myopathy. Positive predictive values for myopathy were calculated for CK (0.32), EMG (0.66), ultrasound (0.47), and muscle biopsy (0.78). All contributed significantly in predicting myopathy. Multivariate analysis yielded a diagnostic algorithm facilitating a more efficient work-up in future patients. CK levels, EMG, ultrasound, and muscle biopsy independently contribute to predicting a myopathy. The diagnostic algorithm shows which combination of ancillary investigations should be employed in different subgroups and when to omit invasive techniques. This algorithm may drastically improve diagnostic efficiency.

No relevant excess prevalence of myotonic dystrophy type 2 in patients with suspected fibromyalgia syndrome.

Myotonic dystrophy type 2 (DM2) is a rare, autosomal dominant, multisystem disorder with proximal weakness, myotonia, pain and cataract as important symptoms. Given the assumed underreporting of DM2 in the Netherlands combined with the predominant role of pain in DM2 as well as in fibromyalgia syndrome (FMS), we hypothesized there will be an excess prevalence of DM2 in patients with (suspected) FMS. Our objective was to determine the prevalence of DM2 in patients with suspected FMS. A prevalence of 2% was considered a relevant excess frequency. Between November 2011 and April 2014, 398 patients with suspected FMS who had been assessed by a rheumatologist participated in this cross-sectional study. 95% of the study population was female, with a mean age of 42 years. The final ICD-9 diagnoses were collected, in 96% the diagnosis was FMS. 92% met the 2010 American College of Rheumatology (ACR) diagnostic criteria for FMS. A questionnaire including neuromuscular symptoms was completed. Creatine kinase was determined, and genetic testing for DM2 was conducted in all patients. DM2 was established in only one patient (0.25%, 95% CI 0.04-1.4%), thus disapproving our hypothesis of a relevant prevalence of 2%. Our results suggest that patients with suspected FMS should not routinely be tested for DM2.

RYR1-related myopathies: a wide spectrum of phenotypes throughout life.

BACKGROUND AND PURPOSE: Although several recent studies have implicated RYR1 mutations as a common cause of various myopathies and the malignant hyperthermia susceptibility (MHS) trait, many of these studies have been limited to certain age groups, confined geographical regions or specific conditions. The aim of the present study was to investigate the full spectrum of RYR1-related disorders throughout life and to use this knowledge to increase vigilance concerning malignant hyperthermia. METHODS: A retrospective cohort study was performed on the clinical, genetic and histopathological features of all paediatric and adult patients in whom an RYR1 mutation was detected in a national referral centre for both malignant hyperthermia and inherited myopathies (2008-2012). RESULTS: The cohort of 77 non-related patients (detection rate 28%) included both congenital myopathies with permanent weakness and 'induced' myopathies such as MHS and non-anaesthesia-related episodes of rhabdomyolysis or hyperCKemia, manifested throughout life and triggered by various stimuli. Sixty-one different mutations were detected, of which 24 were novel. Some mutations are present in both dominant (MHS) and recessive modes (congenital myopathy) of inheritance, even within families. Histopathological features included an equally wide spectrum, ranging from only subtle abnormalities to prominent cores. CONCLUSIONS: This broad range of RYR1-related disorders often presents to the general paediatric and adult neurologist. Its recognition is essential for genetic counselling and improving patients' safety during anaesthesia. Future research should focus on in vitro testing by the in vitro contracture test and functional characterization of the large number of RYR1 variants whose precise effects currently remain uncertain.

Myopathy in a 20-year-old female patient with D4ST-1 deficient Ehlers-Danlos syndrome due to a homozygous CHST14 mutation.

We here report on a 20-year-old female patient with EDS due to a homozygous CHST14 single nucleotide deletion resulting in D4ST-1 deficiency, accompanied by muscle hypoplasia and muscle weakness. Findings of muscle ultrasound, electromyography, and muscle biopsy pointed to a myopathy, similarly as in other EDS types. This myopathy probably contributes to the gross motor developmental delay in this type of EDS.

Radicular dysfunction due to spinal deformities in Marfan syndrome at older age: three case reports.

Marfan syndrome is a inherited connective tissue disorder due to mutations in fibrillin-1. It presents with cardiovascular, ocular, skeletal, pulmonary and dural signs and symptoms. Some of the symptoms of later onset are those associated with scoliosis and dural ectasia. This is the enlargement of the neural canal especially in the lower lumbar and sacral region and occurs in over 90% of Marfan patients. We here report three patients with lumbar and/or sacral radiculopathy due to (kypho)scoliosis and dural ectasia with spinal meningeal cysts. The pain, muscle weakness, muscle atrophy, and sensory disturbances illustrate the severe neurological complications which may occur in Marfan syndrome, especially at later age. Awareness of these complications and development of management protocols is essential since life expectancy of Marfan patients has increased. Marfan syndrome might gradually become recognized as an inherited connective tissue disorder with potentially severe neurological complications during ageing.

Strong association between myotonic dystrophy type 2 and autoimmune diseases.

BACKGROUND: Myotonic dystrophy type 2 (DM2) is a dominantly inherited multisystem disorder, characterised by progressive proximal weakness, myotonia, cataracts and cardiac conduction abnormalities. Our clinical impression of an association between DM2 and autoimmune diseases or autoantibody formation has not been published previously. OBJECTIVE: The aim of the present study was to investigate the frequency of autoimmune diseases and serum autoantibodies in patients with DM2 compared with patients with adult onset myotonic dystrophy type 1 (DM1). METHODS: 28 genetically proven Dutch DM2 patients participated in the study and were compared with 51 age and sex matched adult onset DM1 patients. As the primary outcome measure, the presence of an autoantibody or autoreactive T cell associated autoimmune disorder was assessed. As a secondary outcome measure, the presence of autoantibodies in serum (nuclear and non-nuclear antibodies) was assessed in all patients. RESULTS: The frequency of autoimmune diseases (21% vs 2%) and the frequency of autoantibodies (25% vs 2%) were both significantly (p<0.01) higher in DM2 patients compared with DM1 patients. Data on DM1 patients were comparable with the general population. Results were not confounded by smoking, medication use, familial clustering, age or sex. CONCLUSION: The results provide new insight into the clinical picture of DM2. In addition, possible explanations for the association between DM2 and autoimmune diseases are proposed.

Neuromuscular features in Marfan syndrome.

Marfan syndrome is a clinically and allelic heterogeneous, heritable connective tissue disorder with infrequently reported neuromuscular features. This study is the first to delineate these symptoms in a non-selected population. Neuromuscular involvement was evaluated in 10 Marfan patients through a standardized questionnaire, physical examination, nerve conduction study (NCS), needle electromyography (EMG), muscle ultrasound, laboratory investigation, and muscle biopsy. Existing neuroimages were screened for dural ectasia and spinal meningeal cysts. Twenty healthy controls with similar age distribution completed the questionnaire. The results showed that various neuromuscular symptoms occur more frequently in the patients. Four older patients reported muscle weakness, five patients had a mild-to-moderate reduction in vibration sense, and all older patients mentioned mild functional impairments. NCS showed axonal polyneuropathy in four and EMG myopathic and neurogenic changes in all patients. Increased echo intensity and atrophy on muscle ultrasound was found in more than half of the patients. Muscle biopsies obtained in two patients showed myopathic changes in the older, female patient. In conclusion, the majority of Marfan patients exhibited neuromuscular symptoms characterized as myopathy or polyneuropathy or both, and signs of lumbosacral radiculopathy, with symptoms being most pronounced in the older patients. Although meriting corroboration, these findings indicate a need to further the awareness of neuromuscular involvement in this population.

Dysphagia is present but mild in myotonic dystrophy type 2.

The phenotype of myotonic dystrophy type 2 (DM2) shows similarities as well as differences to that of myotonic dystrophy type 1 (DM1). Dysphagia, a predominant feature in DM1, has not yet been examined in DM2. In a recent nationwide questionnaire survey of gastrointestinal symptoms in DM2, 12 out of 29 DM2 patients reported to have difficulty in swallowing for solid food. The aim of the study was to investigate the presence of dysphagia in patients with genetically proven DM2 who reported difficulty in swallowing for solid food at the questionnaire survey. Swallowing function and fiberoptic endoscopic evaluation of swallowing (FEES) were examined by a speech therapist and otorhinolaryngologist, respectively. In DM2 patients who reported difficulty in swallowing the presence of dysphagia could be confirmed (clinically in 100%, by FEES in 88%). A correlation exists between Dysphagia Outcome and Severity Score (DOSS) and age (p=0.05). None of the patients was underweight, and none of the patients had suffered aspiration pneumonia in the past. Dysphagia is present among DM2 patients and is more severe in older patients. However, dysphagia is generally mild, and do not lead to weight loss, or aspiration pneumonia.

Open-label trial of anti-TNF-alpha in dermato- and polymyositis treated concomitantly with methotrexate.

BACKGROUND/AIMS: To determine the efficacy of infliximab combined with weekly methotrexate in drug-naive recent-onset dermatomyositis and polymyositis. METHODS: A multicentre open-label controlled trial was conducted. Disease activity was assessed using patient's and physician's disease activity assessment, manual muscle testing (MMT), handheld dynamometry, and serum CK. The primary objective was to assess the efficacy using MMT after a period of 26 weeks. RESULTS: The study was terminated prematurely because of a low inclusion rate and a high drop-out rate due to disease progression and the occurrence of an infusion reaction. The few patients who did reach the primary endpoint showed improvement in all aspects studied. CONCLUSION: Infliximab combined with weekly methotrexate might be safe and well tolerated in a small subgroup of patients with drug-naive recent-onset myositis. At present, we do not advocate the use of this treatment because treatment response cannot be predicted beforehand.

Clinical neurophysiology of fatigue.

Fatigue is a multidimensional concept covering both physiological and psychological aspects. Chronic fatigue is a typical symptom of diseases such as cancer, multiple sclerosis (MS), Parkinson's disease (PD) and cerebrovascular disorders but is also presented by people in whom no defined somatic disease has been established. If certain criteria are met, chronic fatigue syndrome can be diagnosed. The 4-item Abbreviated Fatigue Questionnaire allows the extent of the experienced fatigue to be assessed with a high degree of reliability and validity. Physiological fatigue has been well defined and originates in both the peripheral and central nervous system. The condition can be assessed by combining force and surface-EMG measurements (including frequency analyses and muscle-fibre conduction estimations), twitch interpolation, magnetic stimulation of the motor cortex and analysis of changes in the readiness potential. Fatigue is a well-known phenomenon in both central and peripheral neurological disorders. Examples of the former conditions are multiple sclerosis, Parkinson's disease and stroke. Although it seems to be a universal symptom of many brain disorders, the unique characteristics of the concomitant fatigue also point to a specific relationship with several of these syndromes. As regards neuromuscular disorders, fatigue has been reported in patients with post-polio syndrome, myasthenia gravis, Guillain-Barré syndrome, facioscapulohumeral dystrophy, myotonic dystrophy and hereditary motor and sensory neuropathy type-I. More than 60% of all neuromuscular patients suffer from severe fatigue, a prevalence resembling that of patients with MS. Except for several rare myopathies with specific metabolic derangements leading to exercise-induced muscle fatigue, most studies have not identified a prominent peripheral cause for the fatigue in this population. In contrast, the central activation of the diseased neuromuscular system is generally found to be suboptimal. The reliability of the psychological and clinical neurophysiological assessment techniques available today allows a multidisciplinary approach to fatigue in neurological patients, which may contribute to the elucidation of the pathophysiological mechanisms of chronic fatigue, with the ultimate goal to develop tailored treatments for fatigue in neurological patients. The present report discusses the different manifestations of fatigue and the available tools to assess peripheral and central fatigue.

Reduced quantitative muscle function in tenascin-X deficient Ehlers-Danlos patients.

The Ehlers-Danlos Syndrome (EDS) is a heterogeneous group of heritable connective tissue disorders. Skeletal muscle features belong to the clinical criteria of EDS and are generally interpreted to result from increased tendon distensibility or exercise avoidance. However, muscle function in EDS has hardly been investigated as such. We performed a pilot study consisting of clinical investigations, electromyography, muscle ultrasound, muscle biopsy, and quantitative muscle function tests on two EDS patients with deficiency of tenascin-X. Quantitative muscle function proved severely reduced despite normal findings on electromyography and muscle biopsy. These findings dispute the interpretation of increased tendon distensibility. We hypothesize that alterations in the extracellular matrix modify myofascial force transmission and thus influence muscle function in EDS.

Distal spinal muscular atrophy as a major feature in adult-onset ataxia telangiectasia.

The authors report four adult-onset ataxia telangiectasia (AT) patients belonging to two families lacking pronounced cerebellar ataxia but displaying distal spinal muscular atrophy. AT was proven by genetic studies showing ATM mutations and a reduced level of ATM. ATM activity, as measured by phosphorylation of p53, was close to normal, indicating that the p53 response is not the only factor in preventing neural damage in anterior horn cells in AT.

Anti-signal recognition particle autoantibodies: marker of a necrotising myopathy.

OBJECTIVE: To elucidate the clinical importance of the anti-signal recognition particle (SRP) autoantibody in patients with myositis. METHODS: Retrospective systematic assessment of the clinical, laboratory and histological characteristics of 23 anti-SRP-positive patients from six European centres. Data were compared with a large group of anti-SRP-negative patients with myositis published previously. RESULTS: Clinically, patients with anti-SRP autoantibodies often had a severe symmetric proximal muscle weakness resulting in marked disability, dysphagia and highly elevated levels of serum creatine kinase. Three patients had typical dermatomyositis rashes. The disease was associated with the occurrence of extramuscular signs and symptoms including interstitial lung disease. No association was found with an increased risk of cardiac involvement, and the disease carried a reasonably favourable prognosis with most patients responding to treatment. None of the patients had the typical histological features of myositis. Most muscle biopsy specimens showed the presence of necrotic muscle fibres and no inflammatory infiltrates. CONCLUSIONS: Anti-SRP autoantibodies are associated with a syndrome of a necrotising myopathy in the spectrum of immune-mediated myopathies that differs from typical polymyositis. Further studies are needed to elucidate the pathogenesis and to clarify the role of the anti-SRP autoantibodies in this unique disease.

Clinical characteristics of patients with myositis and autoantibodies to different fragments of the Mi-2 beta antigen.

OBJECTIVES: To assess the clinical implications of autoantibodies directed against different parts of the Mi-2 beta autoantigen in patients with myositis. METHODS: A systematic assessment of the clinical, laboratory, and histological characteristics of 48 anti-Mi-2 positive patients from six European centres was made. Anti-Mi-2 autoantibodies were determined with an ELISA using four overlapping fragments spanning the entire amino acid sequence of the autoantigen. Data were compared with results for a large group of anti-Mi-2 negative patients with myositis published previously. RESULTS: Anti-Mi-2 autoantibodies were found in dermatomyositis, polymyositis, and inclusion body myositis. In general, myositis with anti-Mi-2 autoantibodies was characterised by relatively mild disease, sometimes accompanied by extra-muscular symptoms, including arthralgia, arthritis, Raynaud's phenomenon, and interstitial lung disease. Cardiac disease was not seen, and treatment response was fair. No differences were found between patients with autoantibodies to different fragments of the Mi-2 beta antigen, except for a potentially increased risk of cancer in patients with antibodies directed to the N-terminal fragment of the autoantigen. CONCLUSIONS: Anti-Mi-2 autoantibodies are not a marker of a specific subtype of myositis. No significant differences between patients with autoantibodies to different fragments of the Mi-2 beta autoantigen are found, with the possible exception of an increased risk of cancer in patients with antibodies to the N-terminal fragment.