An 83-year-old man with cholangiocarcinoma developed immune checkpoint inhibitor-associated myositis after two cycles of durvalumab, presenting with muscle weakness and myalgia. His serum creatine kinase (CK) level peaked at 26,329 U/L. Needle electromyography confirmed a myogenic process, and MRI revealed extensive muscle edema. Muscle biopsy indicated multifocal necrotic fibers. Following steroid treatment, his CK levels normalized and muscle strength returned. This case represents the first reported instance of durvalumab-associated myositis in Korea.
We reported an age 32 male with progressive proximal muscle weakness. The serum creatine kinase was 1,908 IU/L. The muscle biopsy from biceps brachii muscle showed nonspecific myopathic changes. The whole exome sequencing identified a heterozygous variant (c.296A>C) in CAV3. It was previously reported as a likely pathogenic variant. It was also detected in the male’s mother and brother. However, his mother and brother had only hyperCKemia without muscle weakness. Our case showed phenotypic heterogeneity in a family, with the same variant in CAV3.
Sarcoglycanopathies are a rare group of autosomal recessive limb-girdle muscular dystrophies (LGMDs) caused by genetic variants in α-, β-, γ-, or δ-sarcoglycan that maintain membrane integrity and contribute to molecular signal processing. High-throughput nucleotide sequencing was performed in patients with slowly progressive proximal muscle weakness from early childhood with respiratory involvement, which detected a novel homozygous nonsense variant (c.601C>T;p.Gln201Ter) in SGCB. This report informs about the clinical characteristics of LGMD2E (type-2E LGMD) in Korea and provides genetic confirmation of the disease.
Background Magnetic resonance (MR) images are useful for diagnosing myopathy. The purpose of this study was to determine the usefulness of lower-limb MR images in Korean patients with distal myopathy.
Methods We reviewed medical records in the myopathy database from January 2002 to October 2016. We selected 21 patients from 91 unrelated families with distal myopathy: four with GNE myopathy, 11 with dysferlinopathy, and six with ADSSL1 myopathy.
Results Ten (48%) of the 21 patients were men. The ages of the participants at symptom onset and imaging were 19.2 ± 9.5 and 30.4 ± 9.0 years (mean ± standard deviation), respectively. Their grade on the modified Gardner-Medwin and Walton grade was 3.3 ± 1.7. The strength grade of the knee extensors was not correlated with the Mercuri scale for the quadriceps (r = –0.247, p = 0.115). However, the Medical Research Council grades of the knee flexors, ankle dorsiflexors, and ankle plantar flexors were significantly correlated with the Mercuri scale ratings of the knee flexors (r = –0.497, p = 0.001), tibialis anterior (r = –0.727, p < 0.001), and ankle plantar flexors (r = –0.620, p < 0.001), respectively. T1-weighted MR images showed characteristic fatty replacement patterns that were consistent with the causative genes. Unsupervised hierarchical clustering of the Mercuri scale showed that the main factors contributing to the dichotomy were the causative gene and the clinical severity.
Conclusions This study is the first to reveal the usefulness of lower-limb MR images in the differential diagnosis of distal myopathy in Korea.
Background Intravenous immunoglobulin (IVIg) has been administered for various immune-mediated neurological diseases such as autoimmune neuropathy, inflammatory myopathies, and other autoimmune neuromuscular disorders. The purpose of this study is to investigate side effects and complications of IVIg therapy in neuromuscular disorders.
Methods We enrolled 29 patients (age 8~63 years) with IVIg therapy for various neurological diseases including Guillain-Barre syndrome, myasthenia gravis, dermatomyositis, polymyositis, chronic inflammatory demyelinating polyneuropathy, and multifocal motor neuropathy. IVIg therapy was used at a dose of 0.4 g/kg body weight/day for 5 consecutive days.
Results 10 patients (34%) had adverse events. There are adverse events in 16 courses (11%) among total 145 courses. The majority of patients presented with mild side effects, mostly asymptomatic laboratory changes. Rash or mild headache occurred in 3 patients. One patient showed a serious side effect of deep vein thrombosis.
Conclusions IVIg therapy is safe for a variety of immune-mediated neurological diseases in our study.
Background This study was designed to identify the genetic cause in myopathy family with decreased acid-alpha glucosidase activity.
Methods Clinical and laboratory features of two affected family members were analyzed. Then, whole exome sequencing (WES) was performed.
Results The proband (a 54-year-old woman) and her sister (a 57-year-old woman) presented to our neurologic clinic with proximal muscle weakness. They recalled very active and sporty life since adolescence. At the late teens, they first noticed difficulty in climbing stairs. Neurological examination revealed muscle weakness and atrophies of proximal muscles, predominantly at lower limbs. Electromyography revealed chronic myopathic finding and serum creatine kinase level was elevated in the proband. In addition, serum acid-alpha glucosidase activities were decreased in two patients. WES identified compound heterozygous mutations (c.5713C>T and c.937+1G>A) in DYSF, which were previously reported to be an underlying cause of limb-girdle muscular dystrophy 2B.
Conclusions We identified compound heterozygous DYSF mutations in a myopathy family with decreased acid-alpha glucosidase activity. This result demonstrated the usefulness of WES for the diagnosis of limb-girdle muscular dystrophy.
Background Bcl-2 and Bcl-XL has been known to be members of Bcl-2 family for regulation of long-term cell survival.We investigated the expression of Bcl-2 and Bcl-XL in myblast during myogenesis.Methods: Cultured myoblasts from the C2C12 mouse cell line were isolated at the different stages of myoblast andmyotubes. The mRNA levels for Bcl-2 and Bcl-XL were determined by reverse-transcriptase PCR (RT-PCR). Theimmunocytochemical staining using the antibodies for Bcl-2 and Bcl-XL was performed to examine the expression ofBcl-2 and Bcl-XL in cultured C2C12 cells.Results: By immunocytochemistry, Bcl-2 was strong expressed in cultured myoblasts compared with myotubes. Theexpression of Bcl-XL were observed at similar degree in both myoblasts and myotubes. The RT-PCR assay showed thatC2C12 cells expressed both Bcl-2 and Bcl-XL mRNA level with different pattern of expression at differential stage. Thelevel of expression of Bcl-2 mRNA was observed most highly at early stage of myoblasts, but diminished as differentiationprogressed. However, the level of expression of Bcl-XL didn
Miyoshi myopathy (MM) is caused by the mutations of dysferlin gene (DYSF), which impairs the function of dysferlin protein causing muscle membrane dysfunction. We report a patient showing the MM phenotype who has a sister with LGMD 2B phenotype, along with the results of the immunohistochemical and molecular analyses of the DYSF gene. Immunohistochemical analysis noted negative immunoreactivity against dysferlin. Direct DNA sequencing of whole exons of DYSF gene revealed heterozygous nonsense mutations (c.610C>T + c.2494C>T). To our knowledge, this is the first reported MM case with this very combination of heterozygous mutations.
The Neuromuscular junction (NMJ) is the specialized structure between motor nerves and skeletal muscle, which consisted of presynaptic membrane, synaptic cleft and postsynaptic membrane. This complex structures converts nerve action potentials into muscle contraction. It is a target of a various neuroimmunologic disorders due to vulnerable to antibody-mediated attack. The main autoimmune disorders of NMJ are myasthenia gravis (MG)and Lambert-Eaton myasthenic syndrome (LEMS). The understanding of the immunological basis of MG and LEMS has improved in the recent years. This review provides the outline of the anatomy and physiology of the NMJ. It also focuses on recent advance of immunopathogenesis of NMJ disorder.
Inclusion body myositis (IBM) is the most common idiopathic inflammatory myositis in patients over the age of 50 years. Prevalence of IBM varies among countries and ethnic groups. Etiology and pathogenesis of IBM is still unknown. It may be primary degenerative myopathy or autoimmune inflammatory myopathy or both. Asymmetrical weakness of the quadriceps and flexor forearm muscles are the clinical key of IBM. This review covers clinical presentation, pathogenesis, diagnosis and treatment of IBM.
Rhabdomyolysis is commonly defined as elevation of serum creatine kinase (sCK) level of above 10 times the upper limit of normal followed by a rapid decrease to normal values. Typical clinical features are myalgia, muscular weakness and black colored urine and the most common complication is acute renal failure due to acute tubular necrosis as a result of mechanical obstruction by myoglobin. Most patients experience one episode of rhabdomyolysis by substance abuse, medication, trauma, or seizures. When patients have a history of recurrent rhabdomyolysis, exercise intolerance or family members with neuromuscular disorders, further evaluations for genetic neuromuscular disorder are required. Mortality rate of rhabdomyolysis is, generally, below 10%, but very high in patients with acute renal failure. So, the management in the acute phase should be performed with maintenance of renal function and restore of metabolic derangements by various conservative managements, such as volume replacement.
Camptocormia, first described by Brodie in 1818, is defined as involuntary forward flexion of thoracolumbar spine. For many years, camptocormia was considered as chronic abnormal flexion of trunk with its origin primarily on psychiatric symptom. However, in these days, it is becoming recognized as a disease of progressive weakness in paravertebral muscles associated with many causes. We report a case with clinical suspicion of focal myopathy demonstrating symmetrical paraspinal muscle atrophy and fatty changes.
Background The Korean Society of Neuromuscular Disorders developed the guideline for the diagnosis of Charcot-Marie-Tooth disease (CMT). The guideline was intended to help readers select appropriate tests and practice systemized diagnostic approach in cases with suspected CMT in Korea. Methods: We developed this guideline of CMT through the de novo process using an evidence- based approach. After systematic review of the literature, eight statements were selected using the Appraisal of Guidelines for Research and Evaluation (AGREE) II process. Results: A total of 17 statements were proposed with the grading system and revised using the modified Delphi method. They were reviewed by external experts before receiving official endorsement from the Korean Society of Neuromuscular Disorders, and disseminated to doctors and other medical professionals for use in clinical practice in Korea. Conclusions: The guideline for proper diagnosis in CMT is presented here. This guideline will continue to be updated and revised periodically.
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