Characteristics of South Korean Patients with Hereditary Transthyretin Amyloidosis

BACKGROUND AND PURPOSE: This retrospective cross-sectional study included 18 patients from unrelated families harboring mutations of the transthyretin gene (TTR), and analyzed their characteristics and geographical distribution in South Korea. METHODS: The included patients had a diagnosis of systemic amyloidosis, clinical symptoms, such as amyloid neuropathy or cardiomyopathy, and confirmation of a TTR gene mutation using genetic analysis recorded between April 1995 and November 2014. RESULTS: The mean age at disease onset was 49.6 years, and the mean disease duration from symptom onset to diagnosis was 3.67 years. Fifteen of the 18 patients were classified as mixed phenotype, 2 as the neurological phenotype, and only 1 patient as the cardiac phenotype. The most-common mutation pattern in South Korea was Asp38Ala, which was detected in eight patients. Thirteen patients reported their family hometowns, and five of the eight harboring the Asp38Ala mutation were from the Gyeongsang province in southeast Korea. The other eight patients exhibited a widespread geographical distribution. A particularly noteworthy finding was that the valine at position 30 (Val30Met) mutation, which was previously reported as the most-common TTR mutation worldwide and also the most common in the Japanese population, was not detected in the present South Korean patients. CONCLUSIONS: South Korean patients with hereditary TTR amyloidosis exhibited heterogeneous TTR genotypes and clinical phenotypes. The findings of this study suggest that the distribution of TTR amyloidosis in South Korea is due to de novo mutations and/or related to the other countries in East Asia.

Repetitive Nerve Stimulation in MuSK-Antibody-Positive Myasthenia Gravis

BACKGROUND AND PURPOSE: Responses to repetitive nerve stimulation (RNS) in patients with muscle-specific tyrosine kinase (MuSK) antibody (Ab)-positive myasthenia gravis (MG) vary depending on the muscles tested. We analyzed the RNS responses of limb and facial muscles in MuSK-Ab-positive and acetylcholine receptor (AChR)-Ab-negative MG (MuSK MG) and MuSK-Ab-negative and AChR-Ab-negative [double-seronegative (DSN)] MG patients. METHODS: We retrospectively compared RNS responses between 45 MuSK MG and 29 DSN MG. RNS was applied to the abductor digiti minimi, flexor carpi ulnaris, trapezius, orbicularis oculi, and nasalis muscles. RESULTS: Abnormal RNS responses in limb muscles were observed in 22.2 and 58.6% of MuSK MG and DSN MG patients, respectively, with abnormal facial responses observed in 77.8 and 65.5%, and abnormal responses observed in any of the five muscles in 86.7 and 72.4%. Abnormal RNS responses in the abductor digiti minimi or flexor carpi ulnaris were less frequent in MuSK MG (8.9 and 15.6%, respectively) than in DSN MG (37.9 and 55.2%), whereas the findings for other muscles were not significantly different between the groups. Abnormal facial responses but normal limb responses were independently associated with MuSK MG (odds ratio=5.224, 95% confidence interval=1.300–20.990). CONCLUSIONS: Abnormal RNS responses primarily in facial muscles without involvement of limb muscles were more pronounced in MuSK MG than in DSN MG. RNS of both facial and limb muscles in AChR-Ab-negative MG can increase the test sensitivity and aid in early suspicion of MuSK MG.

Decremental Responses to Repetitive Nerve Stimulation in X-Linked Bulbospinal Muscular Atrophy

BACKGROUND AND PURPOSE: X-linked bulbospinal muscular atrophy (X-BSMA) is characterized by bulbar and spinal muscular weakness and fasciculations. Although X-BSMA is a motor neuronopathy, there are several reports of myasthenic symptoms or decremental responses to repetitive nerve stimulation (RNS). We report the results of applying the RNS test to 15 patients among 41 with genetically confirmed X-BSMA; these 15 patients complained of fatigue, ease of becoming tired, or early muscular exhaustion. METHODS: The 3-Hz RNS test was performed on the trapezius, nasalis, orbicularis oculi, flexor carpi ulnaris, and abductor digiti quinti muscles. A decrement greater than 10% was considered abnormal. Additionally, a pharmacologic response to neostigmine was identified in three patients. RESULTS: A significant decrement was observed in 67% of patients, and was most common in the trapezius muscle (nine cases). The decrement of the trapezius muscle response ranged from 15.9% to 36.9%. The decrement was inversely correlated with the amplitude of compound muscle action potentials at rest. Neostigmine injection markedly improved the decrement in three patients, who showed noticeable decremental responses to 3-Hz RNS. CONCLUSIONS: This study shows that myasthenic symptoms and abnormal decremental responses to low-rate RNS are common in X-BSMA.

A Case of Acute Polyneuropathy with Nephrotic Syndrome Showing Transient Proximal Sensory Conduction Defects

Acute sensorimotor polyneuropathy that resembles Guillain-Barre syndrome (GBS) is rarely accompanied with nephrotic syndrome, and its underlying immunological mechanisms are unclear. A 56-year-old man presented with simultaneous acute progressive symmetric sensorimotor polyneuropathy and proteinuria. A kidney biopsy revealed focal segmental glomerulosclerosis. Serial electrophysiologic studies showed only a transient proximal conduction block in the median nerve, stimulated somatosensory evoked potential and prolonged terminal latencies of the median and peroneal nerves. The patient's neurologic deficits and kidney dysfunction recovered with corticosteroid treatment. Our case showed that somatosensory evoked potential study can be an important objective tool in the diagnosis of acute polyneuropathy with normal distal nerve conduction and that corticosteroids should be considered in the initial treatment of GBS-resembling polyneuropathy associated with nephrotic syndrome.

Erratum: Comparison between Clinical Disabilities and Electrophysiological Values in Charcot-Marie-Tooth 1A Patients with PMP22 Duplication

The publisher wishes to apologize for incorrectly displaying the author (Seok Beom Gwon) name. We correct his name from Seok Beom Gwon to Seok Beom Kwon.

Sequential Involvement of the Nervous System in Subacute Combined Degeneration

PURPOSE: Subacute combined degeneration (SCD) involves progressive degeneration of the spinal cord, optic nerve, and peripheral nerves. Vitamin B12 (VB12) is a co-factor in myelin synthesis. Because each cell that constitutes the myelin component in the central nervous system and peripheral nervous system is different, it is improbable that these cells undergo simultaneous degeneration. However, the sequence of degeneration in SCD has not been established. MATERIALS AND METHODS: In this study, we analysed medical records and electrophysiological data of patients who showed neurological symptoms and whose serum VB12 levels were lower than 200 pg/mL. RESULTS: We enrolled 49 patients in this study. Their mean VB12 level was 68.3 pg/mL. Somatosensory evoked potential (SEP) study showed abnormal findings in 38 patients. Of the 40 patients who underwent visual evoked potential (VEP) study, 14 showed abnormal responses. Eighteen patients showed abnormal findings on a nerve conduction study (NCS). In this study, abnormal posterior tibial nerve SEPs only were seen in 16 patients, median nerve SEPs only were seen in 3 patients, abnormal VEPs only in two, and abnormal NCS responses in one patient. No patient complained of cognitive symptoms. CONCLUSION: In SCD, degeneration appears to progress in the following order: lower spinal cord, cervical spinal cord, peripheral nerve/optic nerve, and finally, the brain.

Comparison between Clinical Disabilities and Electrophysiological Values in Charcot-Marie-Tooth 1A Patients with PMP22 Duplication

BACKGROUND AND PURPOSE: Charcot-Marie-Tooth disease (CMT) type 1A (CMT1A) is the demyelinating form of CMT that is significantly associated with PMP22 duplication. Some studies have found that the disease-related disabilities of these patients are correlated with their compound muscle action potentials (CMAPs), while others have suggested that they are related to the nerve conduction velocities. In the present study, we investigated the correlations between the disease-related disabilities and the electrophysiological values in a large cohort of Korean CMT1A patients. METHODS: We analyzed 167 CMT1A patients of Korean origin with PMP22 duplication using clinical and electrophysiological assessments, including the CMT neuropathy score and the functional disability scale. RESULTS: Clinical motor disabilities were significantly correlated with the CMAPs but not the motor nerve conduction velocities (MNCVs). Moreover, the observed sensory impairments matched the corresponding reductions in the sensory nerve action potentials (SNAPs) but not with slowing of the sensory nerve conduction velocities (SNCVs). In addition, CMAPs were strongly correlated with the disease duration but not with the age at onset. The terminal latency index did not differ between CMT1A patients and healthy controls. CONCLUSIONS: In CMT1A patients, disease-related disabilities such as muscle wasting and sensory impairment were strongly correlated with CMAPs and SNAPs but not with the MNCVs or SNCVs. Therefore, we suggest that the clinical disabilities of CMT patients are determined by the extent of axonal dysfunction.

A Case of Lambert-Eaton Myasthenic Syndrome with Small-Cell Lung Cancer and Transient Increase in Anti-Acetylcholine-Receptor-Binding Antibody Titer

BACKGROUND: Lambert-Eaton myasthenic syndrome (LEMS) is a presynaptic neuromuscular junction disorder that is most frequently associated with small-cell lung cancer (SCLC). The titers of antibodies against voltage-gated calcium channels are frequently increased in LEMS, but only rarely is titer of anti-acetylcholine-receptor-binding antibodies (AChR-abs) increased. CASE REPORT: A 57-year-old male was admitted to our hospital due to dry mouth and eyes and progressive proximal limb weakness of 2 months duration. The results of a repetitive nerve stimulation test disclosed all criteria for the electrophysiological LEMS pattern, and the patient's AChR-abs titer was 0.587 nmol/L. At a follow-up performed 5 years after successful treatment of SCLC and LEMS, his AChR-abs titer had decreased to 0.001 nmol/L. CONCLUSIONS: We suggest that this was a case of transient pseudopositivity of AChR-abs in SCLC with LEMS.

Heterogeneous Characteristics of Korean Patients with Dysferlinopathy

Dysferlinopathy is caused by mutations in the DYSF gene. To characterize the clinical spectrum, we investigated the characteristics of 31 Korean dysferlinopathy patients confirmed by immunohistochemistry. The mean age of symptom onset was 22.23 +/- 7.34 yr. The serum creatine kinase (CK) was highly increased (4- to 101-fold above normal). The pathological findings of muscle specimens showed nonspecific dystrophic features and frequent inflammatory cell infiltration. Muscle imaging studies showed fatty atrophic changes dominantly in the posterolateral muscles of the lower limb. The patients with dysferlinopathy were classified by initial muscle weakness: fifteen patients with Miyoshi myopathy phenotype (MM), thirteen patients with limb girdle muscular dystrophy 2B phenotype (LGMD2B), two patients with proximodistal phenotype, and one asymptomatic patient. There were no differences between LGMD2B and MM groups in terms of onset age, serum CK levels and pathological findings. Dysferlinopathy patients usually have young adult onset and high serum CK levels. However, heterogeneity of clinical presentations and pathologic findings upon routine staining makes it difficult to diagnose dysferlinopathy. These limitations make immunohistochemistry currently the most important method for the diagnosis of dysferlinopathy.

Myopathy With Anti Signal Recognition Particle Antibody

Myopathies associated with anti-signal-recognition particle (SRP) antibodies usually present with severe muscle weakness and exhibit necrotizing myopathy with little inflammation pathologically. Here we report a case of a 61-year-old man who presented with subacute progressive proximal muscle weakness, dysarthria, and dysphagia. Although polymyositis was expected clinically, muscle biopsy revealed myopathic changes with degenerating fibers without definite inflammation. Further laboratory study revealed that the patient was positive for anti-SRP antibodies.

Repetitive Nerve Stimulation Test in Amyotrophic Lateral Sclerosis with Predominant Oropharyngeal Manifestations

BACKGROUND AND PURPOSE: Amyotrophic lateral sclerosis (ALS) patients display easy fatigability and abnormal decrements on repetitive nerve stimulation (RNS) test of clinically involved limb muscles, which can result in ALS being misdiagnosed as myasthenia gravis. We retrospectively analyzed the RNS tests of ten ALS patients with only or predominant oropharyngeal symptoms without ocular or facial weakness. METHODS: RNS tests were performed on the abductor digiti quinti, flexor carpi ulnaris, orbicularis oculi (OO), nasalis and trapezius muscles at low-rate stimulation frequencies of 3 and 5-Hz. Decrements greater than 10% of the compound muscle action potential amplitude on the fifth stimulation compared to the first was regarded as abnormal. RESULTS: Six patients complained of muscular fatigue or diurnal fluctuation. Among the ten patients, three exhibited abnormal decrements during low-rate stimulation in the facial muscles but not in the limb muscles, two exhibited abnormal decrements in the OO and nasalis muscles, and one exhibited abnormal decrements in the OO muscle. CONCLUSIONS: These findings show that the facial muscles may be involved in some early oropharyngeal forms of ALS, although facial weakness may not be clinically evident. We confirm herein that abnormal decrement of facial muscles to RNS test cannot make a definite diagnose for myasthenia gravis.

Kennedy Disease Showing Prominent Remyelinating Features of Sural Nerve

We report a 55-year-old man with chronic weakness of both legs with recently experienced nasal voice. Despite the absence of sensory symptoms, electrophysiologic studies revealed the presence of sensorimotor polyneuropathy. A sural-nerve biopsy showed remarkable reduction of large myelinated fibers with prominent remyelination. Intravenous immunoglobulin was administered due to suspected chronic demyelinating neuropathy, but had no effect. Abnormal trinucleotide-repeat expansion of the androgen receptor gene was subsequently detected in both the patient and his family. These observation indicate that prominent remyelinating features are not necessarily indicative of demyelinating neuropathy.

Iatrogenic Botulism After Intramuscular Injection of Botulinum Toxin Type A

Botulinum toxin type A (BTA) is widely used for both medical treatment and cosmetic purposes. A 46-year-old woman presented with progressive generalized weakness and dysphagia. The patient had injected BTA into her both of her calves by herself for cosmetic purposes. Repetitive nerve stimulation of the right facial nerve demonstrated reduced compound muscle action potential amplitudes of the orbicularis oculi and nasalis muscles, and a reduced response to low-frequency, repetitive stimulation. The possibility of iatrogenic botulism should be considered when using BTA.

Intravascular Lymphomatosis of the Central Nervous System Presenting Progressive Paraparesis

No abstract available.

Clinical Heterogeneity in Korean Patients with Nemaline Myopathy

PURPOSE: Nemaline myopathy (NM) is a clinical heterogeneous congenital myopathy characterized by the presence of subsarcolemmal or cytoplasmic rod-like structures that call nemaline bodies in the muscle fibers. The purpose of this study was to investigate the clinical diversity and pathological features of Korean patients with NM. MATERIALS AND METHODS: Eight patients underwent analyses of clinical manifestations by a structured protocol. Diagnoses were established by a muscle biopsy. RESULTS: Two patients had the typical congenital type, which exhibited neonatal hypotonia and delayed motor milestone, and five patients had the childhood onset type, which exhibited mild gait disturbance as a first symptom. One patient had the adult onset type, which showed acute respiratory failure. Limb weakness was proximal-dominant occurred in six patients. Hyporeflexia was observed in most patients. Elongated faces and high arched palates and feet were also observed. On light microscopy, the nemaline bodies were observed in type 1 and 2 fibers. All patients showed type 1 predominance and atrophy. In the two cases in which ultrastructural studies were performed, typical nemaline rods and disorganized myofibrillar apparatus were detected. CONCLUSION: In conclusion, the eight Korean patients in this study with NM shared common clinical expressions such as proximal limb weakness, reduced deep tendon reflex, and dysmorphic features. This study, however, showed that clinical heterogeneity ranged from typical congenital, mildly affected childhood to the adult onset form with acute respiratory failure. The pathological findings in this study were in accordance with those of other previous reports.

Clinical Characteristics and Outcomes of Juvenile and Adult Dermatomyositis

Dermatomyositis (DM) is an idiopathic inflammatory myopathy with bimodal onset age distribution. The age of onset is between 5-18 yr in juvenile DM and 45-64 yr in adult DM. DM has a distinct clinical manifestation characterized by proximal muscle weakness, skin rash, extramuscular manifestations (joint contracture, dysphagia, cardiac disturbances, pulmonary symptoms, subcutaneous calcifications), and associated disorders (connective tissue disease, systemic autoimmune diseases, malignancy). The pathogenesis of juvenile and adult DM is presumably similar but there are important differences in some of the clinical manifestations, associated disorders, and outcomes. In this study, we investigated the clinical characteristics and outcomes of 16 patients with juvenile DM and 48 with adult DM. This study recognizes distinctive characteristics of juvenile DM such as higher frequency of neck muscle involvement, subcutaneous calcifications, and better outcomes.

Clinical Features and Genetic Analysis of Fascioscapulohumeral Muscular Dystrophy

BACKGROUND: Facioscapulohumeral muscular dystrophy (FSHD) is associated with contractions of the polymorphic D4Z4-repeat array in 4q35 and has the distinctive clinical presentation of an initial involvement of the facial, shoulder-girdle, and upper-arm muscles. The aim of the present study was to determine clinical characteristics in Korean patients with FSHD and potential relationships between contracted D4Z4-repeat size and the FSHD phenotype. METHODS: We studied 34 genetically confirmed patients who had repeat sizes less than 38 kb, and analyzed their clinical manifestations with a structured protocol. The expressed phenotypes were scored according to the Clinical Severity Score formulated by Ricci and van Overveld. RESULTS: The clinical spectrum ranged widely, from asymptomatic individuals with minimal signs to wheelchair- bound patients. The initial affects were mainly in the facial muscles (68.8%), followed by the shoulder-girdle muscle (28.1%). Asymmetric features of the face and shoulder girdle were also important findings (71.9% and 90.0%, respectively). Winging scapular (87.5%), transverse smile (84.4%), Beevor's sign (68.8%), and sleeping with eyes opened (59.4%) were clinically important signs. There was a significant negative correlation between repeat size and clinical severity (r=-0.38, p=0.03). CONCLUSIONS: Distinctive clinical characteristics of FSHD are descending progression and asymmetric distribution of the muscle weakness. Our results also confirmed that the severity of FSHD increases with decreasing D4Z4-repeat size.

Two Cases of Delayed Post-radiation Lower Cranial Nerve Palsies

Radiation-induced lower cranial neuropathy shows a clinical presentation similar to tumor recurrence or amyotrophic lateral sclerosis. We experienced two patients with bulbar palsies several years after radiotherapy for nasopharyngeal cancer. Brain magnetic resonance imaging showed no evidence of tumor recurrence. Electrophysiologic studies demonstrated mild denervation changes and myokymic discharges in muscles innervated by cranial nerves. Bulbar palsies progressed for 1 year then became stable. We emphasize the importance of myokymic discharges in the differential diagnosis of radiation-induced cranial neuropathy as radiation plexopathies.

The Clinical and Pathological Characteristics of Polymyositis Using ENMC Diagnostic Criteria / 대한류마티스학회지

OBJECTIVE: Polymyositis (PM) has known to be the most common type of idiopathic inflammatory myopathy (IIM). However, recent immunopathological studies demonstrated that PM was overdiagnosed previously due to suboptimal classification system. Using newly proposed classification system, we investigated the frequency, clinical and pathological characteristics of PM. METHODS: Among the patients diagnosed as IIM during past 6 years, we classified a 'definite' or 'probable PM' using the European Neuromuscular Center (ENMC) diagnostic criteria. The findings of clinical, laboratory and pathological findings were analyzed. Response to treatment was assessed at 6 months after treatment. RESULTS: Of total 97 cases with IIM, twenty-three cases (24%) were satisfactory to the diagnostic criteria for PM (definite=5 and probable=18). Most cases were young adults, and female predominance was found. All cases showed proximal muscle weakness, and about two-thirds of patients showed extramuscular manifestation. One (4%) had breast cancer, and accompanying connective tissue disorders (CTDs) were found in 3 cases (13%), two of which had systemic sclerosis. Interstitial pneumonia was found in one case (4%). All cases showed marked elevation of serum creatine kinase level. On muscle biopsy, there were endomysial mononuclear cell infiltrations in all cases. Three-fourths of patients responded to immunosuppressant therapy (74%). CONCLUSION: Using ENMC criteria, the frequency of PM was lower than that had been reported previously. The results of clinical characteristics, response to therapy and clinical outcome were similar to the previous reports. However, association of malignancy or CTDs was low in PM.

Clinical and Electrophysiological Characteristics of Leprous Neuropathy

BACKGROUND: It is important to consider leprosy as a cause of peripheral neuropathy, as it is readily treatable. We analyzed clinical and electrodiagnostic characteristics of leprosy patients with peripheral nerve involvement. METHODS: This study was a retrospective analysis of nerve conduction studies (NCS) and the medical records of 10 patients with leprosy were confirmed by a skin or nerve biopsy. NCS using a conventional surface technique were performed in 15 upper extremities and 14 lower extremities. RESULTS: Among ten patients, three patients presented with mononeuropathy, and the others with mononeuropathy multiplex. Five patients had medical histories of leprosy treatment. The patterns of peripheral neuropathies were mononeuropathy multiplex except for one who had an ulnar mononeuropathy. On motor NCS, low or absent CMAPs were most common abnormalities followed by slow conduction velocity and prolonged terminal latency. Sensory NCS also showed changes of amplitudes rather than in conduction velocity. The conduction block of CMAPs with or without dispersion were observed in 5 patients usually on the ulnar nerve at the forearm. CONCLUSIONS: In most instances, leprous patients with neuropathy presented with mononeuropathy multiplex affecting the sensory and motor nerves. NCS showed more likely axonal than demyelinating changes, but the conduction blocks were also found frequently at the forearms.