Paramyotonia congenita (PMC) is characterized by nondystrophic myotonia aggravated by exercise and cold exposure. SCN4A mutations manifest as various phenotypes of channelopathy, including PMC, myotonia congenita, and periodic paralysis. SCN4A-related channelopathy is characterized by autosomal dominant inheritance. Parental gonadal mosaicism is suspected in cases of recurrent de novo mutation in an autosomal dominantly inherited disease. We report a case of two Korean brothers presenting with PMC due to same de novo SCN4A point mutation, probably due to parental gonadal mosaicism.

Tram-track and doughnut-shaped enhancements of the optic nerve sheath in axial and coronal magnetic resonance imaging (MRI) views, respectively, play crucial roles in the diagnosis of optic nerve sheath meningioma (ONSM). However, this finding is not specific to ONSM since it can also be observed in optic perineuritis (OPN). Here we report a 42-year-old female with ONSM who presented with clinical and MRI findings similar to those of OPN.

Citations

• Freiburg Neuropathology Case Conference: Progressive Optic Nerve Lesion Over a 16-Year Period
  I. E. Duman Kavus, R. Sankowski, R. Rölz, A. Dressing, M. Prinz, H. Urbach, D. Erny, C. A. Taschner
  Clinical Neuroradiology.2025; 35(1): 215.     CrossRef

Some cases of myasthenia gravis (MG) with abnormal spontaneous activity (ASA) in needle electromyography (EMG) have been reported, but the associated clinical characteristics remain to be fully elucidated. We report the case of a 36-year-old male with MG in whom ASA was observed. This study highlights that ASA may appear in needle EMG in patients with severe MG who predominantly have bulbar and/or respiratory involvement. Care is needed because this often accompanies myopathic features and can be misdiagnosed as myopathy.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disorder with numerous causes that include genetic factors. Efforts to reveal the genetics of ALS have identified several candidate genes that are associated with familial and sporadic ALS. Here we report a Korean ALS patient who showed prominent upper motor-neuron-related symptoms with marked brain atrophy and neuropsychological deficits. The findings were highly suggestive of ALS in a patient with a likely pathogenic FIG4 variant.

Citations

• Nanoparticles encapsulating phosphatidylinositol derivatives promote neuroprotection and functional improvement in preclinical models of ALS via a long-lasting activation of TRPML1 lysosomal channel
  Valentina Tedeschi, Valeria Nele, Valeria Valsecchi, Serenella Anzilotti, Antonio Vinciguerra, Laura Zucaro, Maria Josè Sisalli, Chiara Cassiano, Nunzia De Iesu, Giuseppe Pignataro, Lorella Maria Teresa Canzoniero, Anna Pannaccione, Giuseppe De Rosa, Agne
  Pharmacological Research.2024; 210: 107491.     CrossRef

The patients with myotonic dystrophy (MD) show ocular motor abnormalities including strabismus, vergence deficits, and inaccurate or slow saccades. Two theories have been proposed to explain the oculomotor deficits in MD. The central theory attributes the defects of eye movements of MD to the involvement of the central nervous system while the muscular theory attributes to dystrophic changes of the extraocular muscles. A 58-year-old woman with MD showed selective slowing of horizontal saccades and reduced peak velocities for both horizontal canals in head impulse tests, while smooth-pursuit eye movements and vertical head impulse responses were normal. This case suggests that the extraocular muscles-as a final common pathway of the voluntary saccade and reflexive vestibular eye movements-may better explain the defective rapid eye movements observed in MD.

Intravenous immunoglobulin (IVIG) is a safe treatment to treat various neurological disorders, but fatal thrombotic events as rare complications have been reported. A 54-year-old woman with Guillain-Barre syndrome complained of dyspnea during IVIG treatment. She was finally diagnosed with pulmonary thromboembolism. To the best of our knowledge, this is the first case of pulmonary thromboembolism associated with IVIG treatment in a Korean patient with Guillain-Barre syndrome.

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Channelopathies are caused by genetically altered excitability of the sarcolemma that manifests in the clinical state of myotonia or paralysis. In accordance to these symptoms they can be classified into non-dystrophic myotonia and periodic paralysis. The evaluation of this heterogeneous group of disease can be made by clinical history, neurological examination, laboratory tests, electrophysiological studies and genetic analysis. Currently SCN4A, CACNA1S, CLCN1 and KCJN2 are most common mutations that cause muscle channelopathies. The phenotype-genotype correlation and evaluation has become an important issue and significant progress in understanding the patho-mechanism has been observed. However clinical and genetic overlaps exist between the disease and further studies are required to elucidate on the remaining unrevealed mechanism of channelopathies. The aim of this review is to provide an overview of different clinical symptoms observed in muscle channelopathies and an appropriate methodology in its genetic evaluation.