Whole-exome sequencing reveals the major genetic factors contributing to neuromyelitis optica spectrum disorder in Chinese patients with aquaporin 4-IgG seropositivity

Clinical analysis and literature review of two paediatric cases of anti-IgLON5 antibody-related encephalitis

Introduction

Anti-IgLON5 antibody-related encephalitis is a rare autoimmune disorder of the central nervous system, predominantly occurring in middle-aged elderly individuals, with paediatric cases being exceptionally rare. This study aims to enhance the understanding of paediatric anti-IgLON5 antibody-related encephalitis by summarising its clinical and therapeutic characteristics.

Method

A retrospective analysis was conducted on two paediatric patients diagnosed with anti-IgLON5 antibody-related encephalitis at Hunan Children's Hospital from August 2022 to November 2023. This involved reviewing their medical records and follow-up data, in addition to a literature review.

Results

The study involved two patients, one male and one female, aged between 2.5 and 9.6 years, both presenting with an acute/subacute course of illness. Clinically, both exhibited movement disorders (including dystonia, involuntary movements, and ataxia), cognitive impairments, sleep disturbances, and psychiatric symptoms. Patient 1 experienced epileptic seizures, while Patient 2 exhibited brainstem symptoms and abnormal eye movements. Neither patient showed autonomic dysfunction. Patient 1 had normal cerebrospinal fluid (CSF) and Brain MRI findings, whereas Patient 2 showed moderate leukocytosis and mild protein elevation in the CSF, and Brain MRI revealed symmetrical lesions in the basal ganglia and cerebellum. Oligoclonal bands in the CSF were positive in both cases. Both patients tested negative for HLA-DQB*05:01 and HLA-DRB*10:01. They received both first-line and second-line immunotherapies, with Patient 2 showing a poor response to treatment.

Discussion

Paediatric cases of anti-IgLON5 antibody-related encephalitis similarly present sleep disturbances as a core symptom, alongside various forms of movement disorders. Immunotherapy is partially effective. Compared to adult patients, these paediatric cases tend to exhibit more pronounced psychiatric symptoms, a more rapid onset, and more evident inflammatory changes in the CSF. The condition appears to have a limited association with HLA-DQB*05:01 and HLA-DRB*10:01 polymorphisms.

A comprehensive review of the advances in neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) is a rare relapsing neuroinflammatory autoimmune astrocytopathy, with a predilection for the optic nerves and spinal cord. Most cases are characterised by aquaporin-4-antibody positivity and have a relapsing disease course, which is associated with accrual of disability. Although the prognosis in NMOSD has improved markedly over the past few years owing to advances in diagnosis and therapeutics, it remains a severe disease. In this article, we review the evolution of our understanding of NMOSD, its pathogenesis, clinical features, disease course, treatment options and associated symptoms. We also address the gaps in knowledge and areas for future research focus.

Research progress on pathogenesis and clinical treatment of neuromyelitis optica spectrum disorders (NMOSDs)

Neuromyelitis optica spectrum disorders (NMOSDs) are characteristically referred to as various central nervous system (CNS)-based inflammatory and astrocytopathic disorders, often manifested by the axonal damage and immune-mediated demyelination targeting optic nerves and the spinal cord. This review article presents a detailed view of the etiology, pathogenesis, and prescribed treatment options for NMOSD therapy. Initially, we present the epidemiology of NMOSDs, highlighting the geographical and ethnical differences in the incidence and prevalence rates of NMOSDs. Further, the etiology and pathogenesis of NMOSDs are emphasized, providing discussions relevant to various genetic, environmental, and immune-related factors. Finally, the applied treatment strategies for curing NMOSD are discussed, exploring the perspectives for developing emergent innovative treatment strategies.

Origins and immunopathogenesis of autoimmune central nervous system disorders

The field of autoimmune neurology is rapidly evolving, and recent discoveries have advanced our understanding of disease aetiologies. In this article, we review the key pathogenic mechanisms underlying the development of CNS autoimmunity. First, we review non-modifiable risk factors, such as age, sex and ethnicity, as well as genetic factors such as monogenic variants, common variants in vulnerability genes and emerging HLA associations. Second, we highlight how interactions between environmental factors and epigenetics can modify disease onset and severity. Third, we review possible disease mechanisms underlying triggers that are associated with the loss of immune tolerance with consequent recognition of self-antigens; these triggers include infections, tumours and immune-checkpoint inhibitor therapies. Fourth, we outline how advances in our understanding of the anatomy of lymphatic drainage and neuroimmune interfaces are challenging long-held notions of CNS immune privilege, with direct relevance to CNS autoimmunity, and how disruption of B cell and T cell tolerance and the passage of immune cells between the peripheral and intrathecal compartments have key roles in initiating disease activity. Last, we consider novel therapeutic approaches based on our knowledge of the immunopathogenesis of autoimmune CNS disorders.

Clinical and genetic analysis of familial neuromyelitis optica spectrum disorder in Chinese: associated with ubiquitin-specific peptidase USP18 gene variants

BACKGROUND

Familial clustering of neuromyelitis optica spectrum disorder (NMOSD) was present in Chinese. This study was to investigate the clinical characteristics and genetic background of familial NMOSD.

METHODS

Through questionnaires in four medical centres in 2016-2020, we identified 10 families with NMOSD aggregation. The statistical differences of clinical characteristics between familial and sporadic NMOSD (22 cases and 459 cases) were summarised. The whole-exome sequencing (WES) for seven families (13 cases and 13 controls) was analysed, compared with our previous WES data for sporadic NMOSD (228 cases and 1 400 controls). The family-based and population-based association and linkage analysis were conducted to identify the pathogenetic genes, the variant impacts were predicted.

RESULTS

The familial occurrence was 0.87% in Chinese. Familial patients had higher expanded disability status scale score than sporadic patients (p=0.03). The single-nucleotide polymorphism (SNP) rs2252257 in the promoter and enhancer of ubiquitin-specific peptidase USP18 was linked to familial NMOSD (p=7.8E-05, logarithm of the odds (LOD)=3.1), SNPs rs361553, rs2252257 and rs5746523 were related to sporadic NMOSD (p=1.29E-10, 3.45E-07 and 2.01E-09, respectively). Patients with the SNP rs361553 T/T genotype had higher recurrence rate than C/T or C/C genotype (1.22±0.85 vs 0.69±0.57 and 0.81±0.65, p=0.003 and 0.001, respectively). SNPs rs361553 and rs2252257 altered USP18 expression in brain and nerve tissues.

CONCLUSION

Most clinical characteristics of familial NMOSD were indistinguishable from sporadic NMOSD except for the worst episodes severity. USP18 with impaired intronic regulatory function contributed to the pathogenesis of NMOSD.

Genetics behind Cerebral Disease with Ocular Comorbidity: Finding Parallels between the Brain and Eye Molecular Pathology

Cerebral visual impairments (CVIs) is an umbrella term that categorizes miscellaneous visual defects with parallel genetic brain disorders. While the manifestations of CVIs are diverse and ambiguous, molecular diagnostics stand out as a powerful approach for understanding pathomechanisms in CVIs. Nevertheless, the characterization of CVI disease cohorts has been fragmented and lacks integration. By revisiting the genome-wide and phenome-wide association studies (GWAS and PheWAS), we clustered a handful of renowned CVIs into five ontology groups, namely ciliopathies (Joubert syndrome, Bardet–Biedl syndrome, Alstrom syndrome), demyelination diseases (multiple sclerosis, Alexander disease, Pelizaeus–Merzbacher disease), transcriptional deregulation diseases (Mowat–Wilson disease, Pitt–Hopkins disease, Rett syndrome, Cockayne syndrome, X-linked alpha-thalassaemia mental retardation), compromised peroxisome disorders (Zellweger spectrum disorder, Refsum disease), and channelopathies (neuromyelitis optica spectrum disorder), and reviewed several mutation hotspots currently found to be associated with the CVIs. Moreover, we discussed the common manifestations in the brain and the eye, and collated animal study findings to discuss plausible gene editing strategies for future CVI correction.

Neuromyelitis Optica Spectrum Disorder: From Basic Research to Clinical Perspectives

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system characterized by relapses and autoimmunity caused by antibodies against the astrocyte water channel protein aquaporin-4. Over the past decade, there have been significant advances in the biologic knowledge of NMOSD, which resulted in the IDENTIFICATION of variable disease phenotypes, biomarkers, and complex inflammatory cascades involved in disease pathogenesis. Ongoing clinical trials are looking at new treatments targeting NMOSD relapses. This review aims to provide an update on recent studies regarding issues related to NMOSD, including the pathophysiology of the disease, the potential use of serum and cerebrospinal fluid cytokines as disease biomarkers, the clinical utilization of ocular coherence tomography, and the comparison of different animal models of NMOSD.

Newly diagnosed neuromyelitis optica spectrum disorders following vaccination: Case report and systematic review

INTRODUCTION

The pathogenesis of neuromyelitis optica spectrum disorder (NMOSD) has been vigorously illustrated, but triggers of the disease remain unclear. Viral infection and vaccination have been observed to precede certain cases of NMOSD. Amidst the Coronavirus disease 2019 (COVID-19) pandemic, mass vaccination takes place across the globe. We report two cases of newly diagnosed NMOSD following COVID-19 vaccination and systematically review previous reports.

METHOD

Searching of Ovid MEDLINE and EMBASE databases was done using predefined search terms related to NMOSD and vaccination. Duplicates were removed. Newly diagnosed NMOSD cases fulfilling the 2015 International Panel for NMO Diagnosis criteria with symptoms presenting between 2-30 days after vaccination were included. Data on age, sex, comorbidity, vaccine name, type, and dose number, duration from vaccination to symptom onset, clinical phenotype(s), MRI findings, CSF profiles, severity of attack, initial and maintenance treatment, number of relapses after vaccination, and clinical outcomes were extracted using a standardized table and compared.

RESULT

Ten cases of postvaccination NMOSD were identified. Patients aged between 15-46 years old. Nine patients (90%) presented with transverse myelitis and 3 (30%) with optic neuritis. The mean duration from vaccination to clinical onset was 8.2 days (median 9 days). Five patients (50%) tested positive for aquaporin 4 (AQP4) antibody. One patient had a family history of NMOSD. Three-fourths of AQP4-IgG seropositive patients with myelopathy had short transverse myelitis. The reported vaccines included CoronaVac, ChAdOx1 nCoV-19, yellow fever, quadrivalent influenza, H1N1 influenza, quadrivalent human papillomavirus, Japanese encephalitis, rabies, and recombinant hepatitis B virus together with tetanus-diphtheria-pertussis vaccines. All patients received high-dose steroids for initial treatment and 2 received additional therapeutic plasma exchange. Maintenance therapy was given in 4 patients. Five patients (50%) experienced no subsequent relapses within the follow-up period ranging between 3-34 months. Almost all patients returned to baseline functional status.

DISCUSSION

The temporal relationship between vaccination and onset of symptoms suggests that vaccine might be a trigger of NMOSD. Genetic predisposition could be a risk factor for postvaccination NMOSD as there are evidences of family history and presence of an associated HLA allele. The prevalence of short-segment transverse myelitis seems to be higher than in typical cases of NMOSD, but the natural history is otherwise similar. All patients received acute treatment with high-dose corticosteroids, most with excellent response. Long-term immunomodulation therapy should be initiated for relapse prevention. Limitations of this study are lack of some relevant data, precision of temporal relationship, and the small number of reports.

CONCLUSION

Postvaccination NMOSD is a rare condition that can occur with various types of vaccines. The short temporal relationship between vaccination and onset of NMOSD and the history of NMOSD in one patient's sibling indicate that vaccine might be a trigger for genetically predisposed individuals.

A Comprehensive Review on the Role of Genetic Factors in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorders (NMOSD) comprise a variety of disorders being described by optic neuritis and myelitis. This disorder is mostly observed in sporadic form, yet 3% of cases are familial NMO. Different series of familial NMO cases have been reported up to now, with some of them being associated with certain HLA haplotypes. Assessment of HLA allele and haplotypes has also revealed association between some alleles within HLA-DRB1 or other loci and sporadic NMO. More recently, genome-wide SNP arrays have shown some susceptibility loci for NMO. In the current manuscript, we review available information about the role of genetic factors in NMO.