ObjectivesWe aimed to define the clinical and serological characteristics of pan-neurofascin antibody-positive patients.MethodsWe tested serum from patients with suspected immune-mediated neuropathies for antibodies directed against nodal/paranodal protein antigens using a live cell-based assay and solid-phase platform. The clinical and serological characteristics of antibody-positive and seronegative patients were then compared. Sera positive for pan-neurofascin were also tested against live myelinated human stem cell-derived sensory neurons for antibody binding.ResultsEight patients with IgG1-subclass antibodies directed against both isoforms of the nodal/paranodal cell adhesion molecule neurofascin were identified. All developed rapidly progressive tetraplegia. Cranial nerve deficits (100% vs 26%), autonomic dysfunction (75% vs 13%) and respiratory involvement (88% vs 14%) were more common than in seronegative patients. Four patients died despite treatment with one or more modalities of standard immunotherapy (intravenous immunoglobulin, steroids and/or plasmapheresis), whereas the four patients who later went on to receive the B cell-depleting therapy rituximab then began to show progressive functional improvements within weeks, became seronegative and ultimately became functionally independent.ConclusionsIgG1 pan-neurofascin antibodies define a very severe autoimmune neuropathy. We urgently recommend trials of targeted immunotherapy for this serologically classified patient group.
Objective: Recent clinical trials have shown that cenobamate substantially improves seizure control in focal-onset drug-resistant epilepsy (DRE). However, little is known about cenobamate's performance in highly active (≥20 seizures/ month) and ultra-refractory focal epilepsy (≥6 failed epilepsy treatments, including antiseizure medications [ASMs], epilepsy surgery, and vagus nerve stimula-How to cite this article:
Increasing availability of next-generation sequencing technologies has revealed several limitations of diagnosis-driven traditional clinicogenetic disease classifications, particularly among patients with an atypical or mixed phenotype. Hereditary spastic paraplegia (HSP) and spinocerebellar ataxia (SCA) are two such disease entities with an often overlapping presentation, in which next generation exome sequencing has played a key role in identification of genes causing disease along a continuum of ataxia and spasticity. We describe a patient who presented with features of both ataxia and spasticity, in whom initial diagnostic testing was inconclusive. Ultimately next generation exome sequencing identified homozygosity for a pathogenic variant in exon 13 of the CAPN1 gene c.1534C>T(p.Arg512Cys). This case supports consideration of a less discriminatory classification system among such patients, potentially allowing for more expedient diagnosis through testing of a larger gene panel along the ‘ataxia-spasticity spectrum’.
Hypokalaemic periodic paralysis typically presents with intermittent mild-to-moderate weakness lasting hours to days. We report a case with an uncommon phenotype of late-onset myopathy without episodic paralytic attacks. Initial work-up including muscle biopsy was inconclusive. A subsequent review of the right deltoid biopsy, long exercise testing and repeated family history was helpful, followed by appropriate genetic testing. We identified a heterozygous pathogenic mutation in calcium ion channel (:c.1583G>A p.Arg528His) causing hypokalaemic periodic paralysis. Myopathy can present without episodic paralysis and the frequency of paralytic episodes does not correlate well with the development and progression of a fixed myopathy. Our report also highlights the intrafamilial phenotypic variation of hypokalaemic periodic paralysis secondary to a gene mutation.
Guillain-Barré syndrome and chronic inflammatory demyelinating polyneuropathy are umbrella terms for a number of pathologically distinct diseases involving disabling, immune-mediated injury to peripheral nerves. Current treatments involve non-specific immunomodulation. Prospective identification of patients with specific disease mechanisms should increasingly inform the use of more targeted disease modifying therapies and may lead to improved outcomes. In this cohort study, we tested serum for antibodies directed against nodal/paranodal protein antigens. The clinical characteristics of antibody positive and seronegative patients were then compared. Eight patients with IgG1-subclass antibodies directed against both isoforms of the nodal/paranodal cell-adhesion molecule neurofascin were identified. All developed rapidly progressive tetraplegia. Cranial nerve deficits (100% versus 26%), autonomic dysfunction (75% versus 13%) and respiratory involvement (88% versus 14%) were more common than in seronegative patients. The response to intravenous immunoglobulin, steroids and/or plasmapheresis was poor. Four patients received the B-cell-depleting therapy rituximab. After several weeks, these patients began to show progressive functional improvements, became seronegative, and were ultimately discharged home. Four patients who did not receive rituximab did not improve and died following the development of infectious complications and/or withdrawal of intensive care support. IgG1 panneurofascin antibodies define a very severe autoimmune neuropathy. We urgently recommend trials of targeted immunotherapy for this serologically-classified patient group.
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