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

Acute pulmonary embolism (PE) is a life-threatening disease that manifests with cardiorespiratory symptoms. Syncope can be a rare, but warning sign of PE. We report a case of a 49-year-old male diagnosed with PE who presented with recurrent syncope prior to typical cardiorespiratory symptoms. His computed tomography pulmonary angiogram revealed bilateral PE. Syncope can be a rare clinical symptom of PE, but considering lethality of the disease, a differential diagnosis of PE should be considered in patients with recurrent syncope.

AGel amyloidosis is an autosomal dominantly inherited disease caused by a GSN mutation, and affected patients typically present with the clinical triad of corneal lattice dystrophy, progressive cranial neuropathy, and cutis laxa. We report a Korean family with AGel amyloidosis with predominant manifestations of facial and bulbar muscle weakness. Whole-exome sequencing revealed a common missense mutation (p.Asp214Tyr) in GSN. This case strongly suggests that AGel amyloidosis should be considered when a patient presents with progressive facial and bulbar palsies.

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.

X-linked Charcot Marie Tooth disease type 1 (CMTX1) is a clinically heterogenous X-linked hereditary neuropathy caused by mutation of the gene encoding gap junction beta 1 protein (GJB1). Typical clinical manifestations of CMTX1 are progressive weakness or sensory disturbance due to peripheral neuropathy. However, there have been some CMTX1 cases with accompanying central nervous system (CNS) manifestations. We report the case of a genetically confirmed CMTX1 patient who presented recurrent transient CNS symptoms without any symptom or sign of peripheral nervous system involvement.