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Background@#and Purpose To understand the characteristics of Korean patients with anti-3-hydroxy-3-methylglutaryl-coenxyme A reductase (HMGCR) myopathy, we measured antiHMGCR antibodies and analyzed the clinical, radiological, and pathological features of patients with anti-HMGCR myopathy. @*Methods@#We measured titers of anti-HMGCR antibodies in the sera of 99 patients with inflammatory myopathy, 36 patients with genetic myopathy, and 63 healthy subjects using an enzyme-linked immunosorbent assay. We tested 16 myositis-specific autoantibodies (MSAs) in all patients with anti-HMGCR myopathy. @*Results@#Positivity for the anti-HMGCR antibody was observed in 17 (4 males and 13 females) of 99 patients with inflammatory myopathy. The median age at symptom onset was 60 years.Ten (59%) of the patients with anti-HMGCR positivity had taken statins. The titer of antiHMGCR antibodies was significantly higher in the statin-naïve group (median=230 U/mL, interquartile range=170–443 U/mL) than in the statin-exposed group (median=178 U/mL, interquartile range=105–210 U/mL, p=0.045). The most common symptom was proximal muscle weakness in 15 patients (88%), followed by myalgia in 9 (53%), neck weakness in 4 (24%), dysphagia in 3 (18%), and skin lesions in 2 (12%). The median titer of anti-HMGCR antibody was 202 U/mL. We found eight different MSAs in nine (53%) patients. The median disease duration from symptom onset to diagnosis was significantly shorter in the MSA-positive group than in the MSA-negative group (p=0.027). @*Conclusions@#Our study was the first to measure anti-HMGCR antibodies in inflammatory myopathy. It has provided new findings, including the suggestion of the coexistence of other MSAs in Korean patients.
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Background@#and Purpose This study aimed to identify the epidemiological features of Guillain-Barré syndrome (GBS) in the Korean population. @*Methods@#Patients with GBS were defined as those who were hospitalized with a primary diagnostic code of G61.0 on the Korean Classification of Disease in a department of neurology, rehabilitation medicine, or pediatrics. We evaluated the incidence and prevalence of GBS as well as physical disability, mortality, and cause of death in patients with GBS from 2002 to 2018 in the Korean population using the Korean National Health Insurance Service database. @*Results@#We identified 11,146 patients with GBS. The ratio of males to females was 1.48. The age-adjusted incidence rate per 100,000 persons increased steadily from 0.84 in 2002 to 1.68 in 2018, as did the age-adjusted prevalence rate per 100,000 persons, from 0.77 to 15.62. The incidence and prevalence of GBS increased with age, peaking at 70–79 years. Among 10,114 patients without physical disability at the time of GBS being diagnosed, 502 (5.0%) patients had moderate disability and 526 (5.2%) had severe disability by the end of the study period.A total of 1,221 (11.0%) patients with GBS died during the mean follow-up period of 17 years (2002–2019). There were 144 (1.3%) in-hospital deaths. @*Conclusions@#This was the first nationwide epidemiological study of patients with GBS covering the entire population including patients of all ages in the Republic of Korea. We have revealed the seasonality of admissions, disability, and long-term mortality rates in patients with GBS.
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Background@#and Purpose The Individualized Neuromuscular Quality of Life questionnaire (INQoL) is a widely used measure of the quality of life in patients with neuromuscular diseases. The purpose of this study was to translate and validate the Korean version of INQoL in Korean patients with neuromuscular diseases. @*Methods@#We translated the original INQoL version into Korean while applying appropriate language adaptations. The internal consistency, known-group validity, and test-retest reliability were also assessed. Construct validity was measured using the modified Rankin Scale (mRS) score and the manual muscle testing (MMT)-sum score based on the Medical Research Council scale, and concurrent validity was measured using the 36-item Short Form Survey (SF-36) questionnaire. @*Results@#This study enrolled 193 patients. The coefficients for internal consistency (Cronbach’s α=0.805 to 0.987) and test-retest reliability (Spearman’s ρ=0.453 to 0.886) were adequately high for all subscales except in the ‘treatment effects’ dimension. INQoL subscales other than those for locking, droopy eyelids, double vision, and swallowing difficulties were significantly associated with their relevant SF-36 domains (Spearman’s ρ=-0.274 to -0.833). Functional status and muscle strength were most strongly associated with independence (Spearman’s ρ=0.753 and p<0.001 for mRS score, Spearman’s ρ=-0.741 and p<0.001 for MMT-sum score). @*Conclusions@#The Korean INQoL is a reliable and validated measurement tool for Korean patients with neuromuscular diseases.
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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.
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Background@#and Purpose Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cellbased assay (CBA) to detect MuSK Abs. @*Methods@#A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). @*Results@#The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen’s kappa=0.880, p<0.001) and ELISA (Cohen’s kappa=0.982, p<0.001). @*Conclusions@#The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.
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Background@#and PurposePathogenic variants in B4GALNT1 have been reported to cause hereditary spastic paraplegia 26. This study has revealed that a novel compound heterozygous pathogenic variant in B4GALNT1 is associated with axonal Charcot-Marie-Tooth disease (CMT). @*Methods@#Whole-exome sequencing (WES) was used to identify the causative factors and characterize the clinical features of a Korean family with sensorimotor polyneuropathy. Functional assessment of the mutant genes was performed using a motor neuron cell line. @*Results@#The WES revealed a compound heterozygous pathogenic variant (c.128dupC and c.451G>A) in B4GALNT1 as the causative of the present patient, a 53-year-old male who presented with axonal sensorimotor polyneuropathy and cognitive impairment without spasticity. The electrodiagnostic study showed axonal sensorimotor polyneuropathy. B4GALNT1 was critical to the proliferation of motor neuron cells. The compensation assay revealed that the pathogenic variants might affect the enzymatic activity of B4GALNT1. @*Conclusions@#This study is the first to identify a case of autosomal recessive axonal CMT associated with a compound heterozygous pathogenic variant in B4GALNT1. This finding expands the clinical and genetic spectra of peripheral neuropathy.
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With the rapid increase in the number of clinical trials in myopathy over the past decade, there is an increasing need for clinical scales to reflect patient’s clinical status. This article outlines the process of identifying possible measures. Detailed consideration has been given to key measures of muscle strength, function, and disability. As well as the usual assessment of the validity and reliability of the measures, three key characteristics were identified as necessary to the assessment of clinical scales used in health care: 1) the type of scale; 2) the clinical significance of the property being measured; and 3) the mathematical properties of the data. Consideration of such aspects facilitates the choice of clinical scales and the interpretation of data.
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Background@#Pompe disease is a rare autosomal recessive disorder caused by the deficiency of a lysosomal enzyme, acid alpha-glucosidase (GAA). Early diagnosis and initiation of treatment with enzyme replacement therapy have remarkable effects on the prognosis of Pompe disease. We performed the expanded screening for late onset Pompe disease (LOPD) at eight centers in Korea. @*Methods@#From September 1, 2015, GAA activity were measured from both dried blood spot (DBS) and mixed leukocyte for 188 available patients. For 12 patients with low GAA activity, we performed Sanger sequencing of GAA gene. @*Results@#Among 188 patients, 115 were males. The mean of age of symptom onset and diagnosis were 34.3 years and 41.6 years. Among 12 patients with decreased GAA activity, two patients were confirmed to have LOPD with genetic test (c.1316T>A [p.M439K] + c.2015G>A [p.R672Q], c.1857C>G [p.S619R] + c.546G>C [leaky splicing]). Other two patients had homozygous G576S and E689K mutation, known as pseudodeficiency allele. @*Conclusions@#This study is expanded study of LOPD screening for targeted Korean population. We found two patients with LOPD, and the detection rate of LOPD is 1.06%. With application of modified GAA cutoff value (0.4), which was previously reported, there were no false positive results of GAA activity test using DBS. Therefore, it could be an appropriate screening test for LOPD in especially East-Asian population, in which pseudodeficiency allele is frequent.
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Purpose@#AGel amyloidosis is systemic amyloidosis caused by pathogenic variants in the GSN gene. In this study, we sought to characterize the clinical and brain magnetic resonance image (MRI) features of Korean patients with AGel amyloidosis. @*Materials and Methods@#We examined 13 patients with AGel amyloidosis from three unrelated families. Brain MRIs were performed in eight patients and eight age- and sex-matched healthy controls. Therein, we analyzed gray and white matter content using voxel-based morphometry (VBM), tract-based spatial statistics (TBSS), and FreeSurfer. @*Results@#The median age at examination was 73 (interquartile range: 64–76) years. The median age at onset of cutis laxa was 20 (interquartile range: 15–30) years. All patients over that age of 60 years had dysarthria, cutis laxa, dysphagia, and facial palsy. Two patients in their 30s had only mild cutis laxa. The median age at dysarthria onset was 66 (interquartile range: 63.5–70) years. Ophthalmoparesis was observed in three patients. No patient presented with muscle weakness of the limbs. Axial fluid-attenuated inversion recovery images of the brain showed no significant differences between the patient and control groups. Also, analysis of VBM, TBSS, and FreeSurfer revealed no significant differences in cortical thickness between patients and healthy controls at the corrected significance level. @*Conclusion@#Our study outlines the clinical manifestations of prominent bulbar palsy and early-onset cutis laxa in 13 Korean patients with AGel amyloidosis and confirms that AGel amyloidosis mainly affects the peripheral nervous system rather than the central nervous system.
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Background@#and Purpose Detecting antibodies against muscle-specific tyrosine kinase (MuSK Abs) is essential for diagnosing myasthenia gravis (MG). We applied an in-house cellbased assay (CBA) to detect MuSK Abs. @*Methods@#A stable cell line was generated using a lentiviral vector, which allowed the expression of MuSK tagged with green fluorescent protein in human embryonic kidney 293 (HEK293) cells. Serum and anti-human IgG antibody conjugated with red fluorescence were added. The presence of MuSK Abs was determined based on the fluorescence intensity and their colocalization in fluorescence microscopy. Totals of 218 serum samples collected from 177 patients with MG, 31 with other neuromuscular diseases, and 10 healthy controls were analyzed. The CBA results were compared with those of a radioimmunoprecipitation assay (RIPA) and an enzyme-linked immunosorbent assay (ELISA). @*Results@#The MuSK-HEK293 cell line stably expressed MuSK protein. The CBA detected MuSK Abs in 34 (19.2%) of 177 samples obtained from patients with MG and in none of the participants having other neuromuscular diseases or in the healthy controls. The clinical characteristics of the patients with MuSK MG determined based on the CBA were strongly correlated with known clinical features of MuSK MG. There was an almost perfect agreement between the results of the CBA and those of the RIPA (Cohen’s kappa=0.880, p<0.001) and ELISA (Cohen’s kappa=0.982, p<0.001). @*Conclusions@#The results of the in-house CBA showed excellent agreement with both the RIPA and ELISA. Our in-house CBA can be considered a reliable method for detecting MuSK Abs.
ABSTRACT
Background@#and PurposePathogenic variants in B4GALNT1 have been reported to cause hereditary spastic paraplegia 26. This study has revealed that a novel compound heterozygous pathogenic variant in B4GALNT1 is associated with axonal Charcot-Marie-Tooth disease (CMT). @*Methods@#Whole-exome sequencing (WES) was used to identify the causative factors and characterize the clinical features of a Korean family with sensorimotor polyneuropathy. Functional assessment of the mutant genes was performed using a motor neuron cell line. @*Results@#The WES revealed a compound heterozygous pathogenic variant (c.128dupC and c.451G>A) in B4GALNT1 as the causative of the present patient, a 53-year-old male who presented with axonal sensorimotor polyneuropathy and cognitive impairment without spasticity. The electrodiagnostic study showed axonal sensorimotor polyneuropathy. B4GALNT1 was critical to the proliferation of motor neuron cells. The compensation assay revealed that the pathogenic variants might affect the enzymatic activity of B4GALNT1. @*Conclusions@#This study is the first to identify a case of autosomal recessive axonal CMT associated with a compound heterozygous pathogenic variant in B4GALNT1. This finding expands the clinical and genetic spectra of peripheral neuropathy.
ABSTRACT
With the rapid increase in the number of clinical trials in myopathy over the past decade, there is an increasing need for clinical scales to reflect patient’s clinical status. This article outlines the process of identifying possible measures. Detailed consideration has been given to key measures of muscle strength, function, and disability. As well as the usual assessment of the validity and reliability of the measures, three key characteristics were identified as necessary to the assessment of clinical scales used in health care: 1) the type of scale; 2) the clinical significance of the property being measured; and 3) the mathematical properties of the data. Consideration of such aspects facilitates the choice of clinical scales and the interpretation of data.
ABSTRACT
Background@#Pompe disease is a rare autosomal recessive disorder caused by the deficiency of a lysosomal enzyme, acid alpha-glucosidase (GAA). Early diagnosis and initiation of treatment with enzyme replacement therapy have remarkable effects on the prognosis of Pompe disease. We performed the expanded screening for late onset Pompe disease (LOPD) at eight centers in Korea. @*Methods@#From September 1, 2015, GAA activity were measured from both dried blood spot (DBS) and mixed leukocyte for 188 available patients. For 12 patients with low GAA activity, we performed Sanger sequencing of GAA gene. @*Results@#Among 188 patients, 115 were males. The mean of age of symptom onset and diagnosis were 34.3 years and 41.6 years. Among 12 patients with decreased GAA activity, two patients were confirmed to have LOPD with genetic test (c.1316T>A [p.M439K] + c.2015G>A [p.R672Q], c.1857C>G [p.S619R] + c.546G>C [leaky splicing]). Other two patients had homozygous G576S and E689K mutation, known as pseudodeficiency allele. @*Conclusions@#This study is expanded study of LOPD screening for targeted Korean population. We found two patients with LOPD, and the detection rate of LOPD is 1.06%. With application of modified GAA cutoff value (0.4), which was previously reported, there were no false positive results of GAA activity test using DBS. Therefore, it could be an appropriate screening test for LOPD in especially East-Asian population, in which pseudodeficiency allele is frequent.
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Facioscapulohumeral muscular dystrophy (FSHD) is an autosomal dominant muscular disorder characterized by weakness of facial, shoulder, abdominal, hip girdle, humeral, and anterior distal leg muscles, with descending progression from the face to the legs in an asymmetric pattern. In about 5% of patients with FSHD, no D4Z4 repeat contraction on chromosome 4q35 is observed;this disease entity is called FSHD2. FSHD2 is characterized by DNA hypomethylation on the 4q-subtelomeric macrosatellite repeat array D4Z4. In Korea, there have been no previous reports of FSHD2. We report the first two cases of FSHD2 in Korea, carrying c.3801delG and c.1580C>T mutations in the SMCHD1 gene, respectively. For rapid and accurate diagnosis of FSHD2, genetic analysis of the D4Z4 haplotype and methylation with next-generation sequencing are required.
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Purpose@#AGel amyloidosis is systemic amyloidosis caused by pathogenic variants in the GSN gene. In this study, we sought to characterize the clinical and brain magnetic resonance image (MRI) features of Korean patients with AGel amyloidosis. @*Materials and Methods@#We examined 13 patients with AGel amyloidosis from three unrelated families. Brain MRIs were performed in eight patients and eight age- and sex-matched healthy controls. Therein, we analyzed gray and white matter content using voxel-based morphometry (VBM), tract-based spatial statistics (TBSS), and FreeSurfer. @*Results@#The median age at examination was 73 (interquartile range: 64–76) years. The median age at onset of cutis laxa was 20 (interquartile range: 15–30) years. All patients over that age of 60 years had dysarthria, cutis laxa, dysphagia, and facial palsy. Two patients in their 30s had only mild cutis laxa. The median age at dysarthria onset was 66 (interquartile range: 63.5–70) years. Ophthalmoparesis was observed in three patients. No patient presented with muscle weakness of the limbs. Axial fluid-attenuated inversion recovery images of the brain showed no significant differences between the patient and control groups. Also, analysis of VBM, TBSS, and FreeSurfer revealed no significant differences in cortical thickness between patients and healthy controls at the corrected significance level. @*Conclusion@#Our study outlines the clinical manifestations of prominent bulbar palsy and early-onset cutis laxa in 13 Korean patients with AGel amyloidosis and confirms that AGel amyloidosis mainly affects the peripheral nervous system rather than the central nervous system.
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BACKGROUND AND PURPOSE: GNE myopathy is a rare progressive myopathy caused by biallelic mutations in the GNE gene, and frequently accompanied by rimmed vacuoles in muscle pathology. The initial symptom of foot drop or hip-girdle weakness eventually spreads to all limbs over a period of decades. Recent advances in pathophysiologic research have facilitated therapeutic trials aimed at resolving the core biochemical defect. However, there remains unsettled heterogeneity in its natural course, which confounds the analysis of therapeutic outcomes. We performed the first large-scale study of Korean patients with GNE myopathy. METHODS: We gathered the genetic and clinical profiles of 44 Korean patients with genetically confirmed GNE myopathy. The clinical progression was estimated retrospectively based on a patient-reported questionnaire on the status of the functional joint sets and daily activities. RESULTS: The wrist and neck were the last joints to lose antigravity functionality irrespective of whether the weakness started from the ankle or hip. Two-thirds of the patients could walk either independently or with an aid. The order of losing daily activities could be sorted from standing to eating. Patients with limb-girdle phenotype showed an earlier age at onset than those with foot-drop onset. Patients with biallelic kinase domain mutations tended to progress more rapidly than those with epimerase and kinase domain mutations. CONCLUSIONS: The reported data can guide the clinical management of GNE myopathy, as well as provide perspective to help the development of clinical trials.
Subject(s)
Humans , Age of Onset , Ankle , Disease Progression , Eating , Extremities , Foot , Hip , Joints , Muscular Diseases , Muscular Dystrophies, Limb-Girdle , Neck , Pathology , Phenotype , Phosphotransferases , Population Characteristics , Retrospective Studies , Surveys and Questionnaires , Vacuoles , WristABSTRACT
BACKGROUND AND PURPOSE: Neurological involvement in Behçet's disease [neuro-Behçet's disease (NBD)] is uncommon, but it is worth investigating since it can cause substantial disability. However, difficulties exist in understanding the clinical features of NBD due to regional variations and the lack of studies utilizing well-established diagnostic criteria. We therefore analyzed the clinical features of patients with NBD based on the recent international consensus recommendation. METHODS: We retrospectively searched electronic databases for patients with Behçet's disease (BD) between 2000 and 2017, and reviewed their medical records. Based on the recent international consensus recommendation, patients with definite or probable NBD were included. RESULTS: Of 9,817 patients with the diagnosis code for BD, 1,682 (17.1%) visited the neurology clinic and 110 (1.1%) were classified as NBD. Ninety-eight patients exhibited parenchymal NBD and 12 exhibited nonparenchymal NBD. Their age at the onset of NBD was 37.6±10.6 years and the male-to-female ratio was 1.24:1. Brainstem syndrome (43.9%) was the most common condition in the 98 patients with parenchymal NBD, followed by multifocal (32.7%) and spinal cord (12.2%) syndromes. 72.4% exhibited acute NBD and 27.6% exhibited a progressive disease course. Frequent manifestations included pyramidal signs (52.0%), headache (45.9%), dysarthria (42.9%), and fever (31.6%). A frequent pattern in brain MRI was an upper brainstem lesion extending to the thalamus and basal ganglia. CONCLUSIONS: Approximately 1% of the patients with suspected BD exhibited NBD. Neurologists must understand the clinical characteristics of NBD in order to perform the differential diagnosis and management of these patients.
Subject(s)
Humans , Basal Ganglia , Brain , Brain Stem , Classification , Consensus , Diagnosis , Diagnosis, Differential , Dysarthria , Fever , Headache , Korea , Magnetic Resonance Imaging , Medical Records , Neurology , Retrospective Studies , Spinal Cord , ThalamusABSTRACT
Congenital fiber type disproportion (CFTD) has been related with mutations in ACTA1, SEPN1, RYR1 and tropomyosin 3 (TPM3) genes. Particularly, TPM3 mutation was identified as one of the most frequent cause of CFTD and was also detected in cap myopathy and nemaline myopathy. Herein we report patients of autosomal dominant TPM3 missense mutations with CFTD in a Korean family over twogenerations. Two of our patients, who developed mild muscle weakness in infancy, presented with altered mentality and respiratory distress despite relatively mild limb weakness.
Subject(s)
Humans , Extremities , Muscle Weakness , Muscular Diseases , Mutation, Missense , Myopathies, Nemaline , Myopathies, Structural, Congenital , Respiratory Insufficiency , Ryanodine Receptor Calcium Release Channel , TropomyosinABSTRACT
Limb-girdle muscular dystrophies (LGMD) are heterogeneous disorders with autosomal inheritance. Autosomal dominant LGMD mapped to 7q36.3 has been classified as LGMD type 1D (LGMD1D) in the Human Gene Nomenclature Committee Database. LGMD1D is characterized predominantly by limb-girdle weakness and may also show a bulbar symptom in some cases. In the past, the frequency of this disease was uncommon, and this disorder was mainly found in Europe and the United States. However, recently, this disorder has been reported in Asia, including Japan, Korea, and Taiwan. Here, we report on three LGMD1D patients, including one with a novel mutation in DNAJB6, c.298T>A. While two patients complained of limb-girdle weakness, as would be expected, one patient had distal weakness. They had various serum creatine kinase levels. Radiologic findings in one patient showed fatty degeneration and atrophy in the posterior part of distal muscles. Pathologic findings in one of the patients showed rimmed vacuoles. Although LGMD1D is still uncommon in Korea, we discovered three Korean patients with LGMD1D, including one novel mutation in DNAJB6, p.Phe100Ile (c.298T>A).