Familial neuromyelitis optica

Interferon Regulatory Factor 5 Gene Polymorphisms and mRNA Expression Levels Are Associated with Neuromyelitis Optica Spectrum Disorder

Interferon regulatory factor 5 (IRF5) is a critical transcription factor in the toll-like receptor signaling pathway. It is associated with autoimmune disorders, such as rheumatoid arthritis, systemic lupus erythematosus, and inflammatory bowel disease. However, the relationship between the functional single nucleotide polymorphisms (SNPs) of IRF5 and its mRNA expression level in patients with neuromyelitis optica spectrum disorder remains unclear. The present study aimed to investigate the relationship between polymorphisms and mRNA expression levels of the IRF5 gene with the incidence of neuromyelitis optica spectrum disorder (NMOSD) in northern Chinese Han people. Two loci of the IRF5 gene (rs2004640 and rs2280714) of 164 patients with NMOSD and 269 healthy subjects were genotyped using the multiple SNaPshot technique. The frequencies of alleles, genotypes, and haplotypes were compared. Stratified analysis was performed according to age, sex, AQP4 status, onset age, and Expanded Disability Status Scale (EDSS) score. The IRF5 mRNA levels in peripheral blood mononuclear cells (PBMCs) of 64 NMOSD patients (32 patients in the acute stage and 32 patients in the remission stage) and 35 healthy subjects were detected by real-time PCR. The association of SNP polymorphisms with the mRNA expression level was determined by nonparametric tests. Allele and genotype frequency distributions of rs2004640 showed significant differences between both groups. Compared to healthy controls, the frequency of rs2004640 T allele markedly increased in patients (OR = 1.51, 95% CI = 1.09-2.08, P = 0.005). Minor allele T and GT genotype of rs2004640 that significantly increases the risk of NMOSD were discovered using genetic inheritance models (codominant, dominant, and overdominant) and haplotype analyses. Subsequent haplotype analyses revealed that the major haplotype "T-A" containing the risk alleles (the SNP sequence of the alleles was rs2004640 and rs2280714) had adverse effects on NMOSD. Based on the stratification analysis according to the EDSS score, the GT genotype frequency in the EDSS ≥ 4 group (38.2%) was markedly lower than that in the EDSS < 4 group (61.8%) (OR = 0.32, 95% CI = 0.15-0.68, P = 0.0054), with a significant difference. The IRF5 mRNA expression level was increased in NMOSD patients compared to that in normal subjects. IRF5 gene polymorphisms may be tightly associated with the genesis and progression of NMOSD in northern Chinese Han people. IRF5 mRNA expression was increased in patients with NMOSD and significantly increased in patients with acute phase. Perhaps IRF5 expression levels can be used as a predictor of disease activity in the future.

Association between TIMP1 polymorphism and female neuromyelitis optica spectrum disorder in Chinese population

Aims

Earlier studies have indicated an association between the TIMP1 polymorphism and the risk of certain autoimmune diseases, as well as a link between higher TIMP1 levels and blood-brain barrier (BBB) disruption in neuromyelitis optica spectrum disorders (NMOSD). This study aimed to explore the correlation between TIMP1 polymorphism and NMOSD phenotypes.

Methods

Genotyping of three loci (rs4898, rs2070584, rs6609533) in the TIMP1 gene was performed in 126 NMOSD patients and 213 healthy controls (HCs) from North China using the SNaPshot sequencing technique, and a correlation analysis was done between phenotypes and TIMP1 genotype.

Results

The frequency of the rs4898-T, rs2070584-T, and rs6609533-G alleles was significantly higher in NMOSD patients than those in HCs (p < 0.05). Accordingly, the rs4898-TT, rs2070584-TT, and rs6609533-GG genotypes were found at a higher frequency in patients than in controls (p < 0.05). Haplotype analysis showed TIMP1 T-T-G (rs4898-rs2070584-rs6609533) frequency was higher in female NMOSD patients (p = 0.019), and the frequency of T-T-G haplotypes in the BBB disrupted group was higher compared with that in the BBB normal group (p = 0.04).

Conclusions

TIMP1 rs4898-T, rs2070584-T, and rs6609533 polymorphism may contribute to the susceptibility of Female NMOSD patients in the Chinese Population. TIMP1 T-T-G (rs4898-rs2070584-rs6609533) haplotype is more common among female NMOSD patients and is linked to heightened disruption of the BBB.

Moving towards a new era for the treatment of neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorders (NMOSD) include a rare group of autoimmune conditions that primarily affect the central nervous system. They are characterized by inflammation and damage to the optic nerves, brain and spinal cord, leading to severe vision impairment, locomotor disability and sphynteric disturbances. In the majority of cases, NMOSD arises due to specific serum immunoglobulin G (IgG) autoantibodies targeting aquaporin 4 (AQP4-IgG), which is the most prevalent water-channel protein of the central nervous system. Early diagnosis and treatment are crucial to manage symptoms and prevent long-term disability in NMOSD patients. NMOSD were previously associated with a poor prognosis. However, recently, a number of randomized controlled trials have demonstrated that biological therapies acting on key elements of NMOSD pathogenesis, such as B cells, interleukin-6 (IL-6) pathway, and complement, have impressive efficacy in preventing the occurrence of clinical relapses. The approval of the initial drugs marks a revolutionary advancement in the treatment of NMOSD patients, significantly transforming therapeutic options and positively impacting their prognosis. In this review, we will provide an updated overview of the key immunopathological, clinical, laboratory, and neuroimaging aspects of NMOSD. Additionally, we will critically examine the latest advancements in NMOSD treatment approaches. Lastly, we will discuss key aspects regarding optimization of treatment strategies and their monitoring.

Immune-Mediated Myelopathies

OBJECTIVE

Immune-mediated myelopathies are conditions in which the immune system attacks the spinal cord. This article describes the distinguishing characteristics of immune-mediated myelopathies and treatment strategies for patients affected by these disorders.

LATEST DEVELOPMENTS

New biomarkers, such as aquaporin 4 and myelin oligodendrocyte glycoprotein antibodies, in the blood and spinal fluid have led to the identification of antigen-specific immune-mediated myelopathies and approved therapies to prevent disease progression.

ESSENTIAL POINTS

The first step in the diagnosis of an immune-mediated myelopathy is confirming that the immune system is the cause of the attack by excluding non-immune-mediated causes. The second step is to narrow the differential diagnosis based on objective biomarkers such as serology and MRI patterns. The third step is to treat the specific immune-mediated myelopathy by using evidence-based medicine.

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.

Causal associations between prodromal infection and neuromyelitis optica spectrum disorder: A Mendelian randomization study

BACKGROUND AND PURPOSE

Prodromal infections are associated with neuromyelitis optica spectrum disorder (NMOSD), but it remains unclear which type of infection has a causal association with NMOSD. We aimed to explore the causal associations between four herpesvirus infections (chickenpox, cold sores, mononucleosis and shingles) and NMOSD, as well as between other types of infections and NMOSD.

METHODS

For data on infections, we used the genome-wide association study (GWAS) summary statistics from the 23andMe cohort. For outcomes, we used the GWAS data of participants of European ancestry, including 215 NMOSD patients (132 anti-aquaporin-4 antibody [AQP4-ab]-positive patients and 83 AQP4-ab-negative patients) and 1244 normal controls. Single-nucleotide polymorphism (SNP) identification and two-sample Mendelian randomization (MR) analyses were then performed.

RESULTS

In the 23andMe cohort, we identified one SNP for chickenpox (rs9266089 in HLA-B gene), one SNP for cold scores (rs885950 in the POU5F1 gene), one SNP for mononucleosis (rs2596465 in the HCP5 gene), and three SNPs for shingles (rs2523591 in the HLA-B gene; rs7047299 in the IFNA21 gene; rs9260809 in the MICD gene). The association between cold sores and AQP4-ab-positive NMOSD reached statistical significance (odds ratio [OR] 745.318; 95% confidence interval [CI] 22.176, 25,049.53 [p < 0.001, Q < 0.001]). The association between shingles and AQP4-ab-positive NMOSD was also statistically significant (OR 21.073; 95% CI 4.271, 103.974 [p < 0.001, Q < 0.001]). No significant association was observed between other infections and AQP4-ab-positive or AQP4-ab-negative NMOSD.

CONCLUSION

These findings suggest there are positive associations between cold sores and shingles and AQP4-ab-positive NMOSD, indicating there may be causal links between herpes simplex virus and varicella-zoster virus infection and AQP4-ab-positive NMOSD.

The Role of MRI in Differentiating Demyelinating and Inflammatory (not Infectious) Myelopathies

Demyelinating and inflammatory myelopathies represent a group of diseases with characteristic patterns in neuroimaging and several differential diagnoses. The main imaging patterns of demyelinating myelopathies (multiple sclerosis, neuromyelitis optica spectrum disorder, acute disseminated encephalomyelitis, and myelin oligodendrocyte glycoprotein antibody-related disorder) and inflammatory myelopathies (systemic lupus erythematosus-myelitis, sarcoidosis-myelitis, Sjögren-myelitis, and Behçet's-myelitis) will be discussed in this article, highlighting key points to the differential diagnosis.

Different clinical phenotypes of AQP4-IgG positive NMOSD in two first degree relatives

BACKGROUND

Neuromyelitis optica spectrum disorder (NMOSD) are autoimmune inflammatory disorders of the CNS in which patients have severe relapses of optic neuritis and myelitis. Aquaporin-4 antibody (AQP4-IgG) positive NMOSD has not been reported in members of the same family in Sub Saharan Africa. We report the uncommon scenario in which both a Ugandan HIV positive woman and her HIV negative daughter were diagnosed with AQP4-IgG positive NMOSD. We discuss pathogenic mechanisms that may underlie familial presentation of AQP4-IgG positive NMOSD.

CASE PRESENTATION

Case 1, a 54-year-old female teacher with a 20-year history of HIV infection and virally suppressed on Tenofovir, Lamivudine and Dolutegravir HAART regimen, presented with 8 months of progressive quadriparesis and urinary incontinence with a T6 sensory level. She had gadolinium enhancing longitudinally extensive transverse myelitis on MRI and was AQP4-IgG positive on serum studies. She received IV Methylprednisone 1 g daily for 3 days as a pulse and was continued on tapering doses of oral Prednisone with maintenance doses of Azathioprine. She showed slow improvements in limb motor function. Her daughter, case 2, is a 35-year-old HIV negative nutritionist, independently ambulant, with no known comorbidities or precedent autoimmune disease. She presented 1 year before her mother's AQP4-IgG positive NMOSD diagnosis with 7 months history of bilateral visual loss of rapid onset, with gadolinium-enhancing optic nerves on Brain and orbit MRI, in keeping with bilateral optic neuritis. She was AQP4-IgG positive on serum studies. She stabilized on tapered doses of oral Prednisone and continues daily oral Azathioprine with moderate improvement in her vision and no further relapses as yet.

CONCLUSIONS

We add to existing literature and hypothesize that NMOSD appears to show a complex genetic background. To our knowledge, this is the first report in Sub-Saharan Africa, of familial AQP4-IgG positive NMOSD presenting with clinical heterogeneity between first degree relatives. A better understanding of the pathogenic mechanisms involved, including genome wide studies for particular risk loci for familial NMOSD, will be pivotal for future preventative and therapeutic strategies.

The neuro-ophthalmological manifestations of NMOSD and MOGAD-a comprehensive review

Optic neuritis (ON) is one of the most frequently seen neuro-ophthalmic causes of vision loss worldwide. Typical ON is often idiopathic or seen in patients with multiple sclerosis, which is well described in the landmark clinical trial, the Optic Neuritis Treatment Trial (ONTT). However, since the completion of the ONTT, there has been the discovery of aquaporin-4 (AQP4) and myelin oligodendrocyte glycoprotein (MOG) antibodies, which are biomarkers for neuromyelitis optica spectrum disorder (NMOSD) and MOG antibody-associated disease (MOGAD), respectively. These disorders are associated with atypical ON that was not well characterised in the ONTT. The severity, rate of recurrence and overall outcome differs in these two entities requiring prompt and accurate diagnosis and management. This review will summarise the characteristic neuro-ophthalmological signs in NMOSD and MOGAD, serological markers and radiographic findings, as well as acute and long-term therapies used for these disorders.

Familial neuromyelitis optica spectrum disorders: Case series and systematic review

BACKGROUND

Neuromyelitis optica spectrum disorders (NMOSD) is considered a complex multifactorial disorder. Most cases are sporadic, and familial NMOSD is assumed as a rare occurrence. However, few studies reported familial aggregation of the disorder.

OBJECTIVES

To report familial NMOSD cases in Thailand and conduct a systematic review of familial NMOSD.

METHODS

A retrospective chart review of familial NMOSD patients at the university hospital was performed. Articles related to "genetic" and "NMOSD" were systematically searched and reviewed. We included NMOSD patients whose one or more relatives were diagnosed with the same disease or multiple sclerosis (MS). Data regarding demographics, clinical features, disease outcomes, and genetic testing were collected and analyzed using descriptive statistics.

RESULTS

We identified 6 familial cases from 165 NMOSD cases (3.6%) at our hospital and gathered 77 cases from a systematic review, totaling 83 cases from 40 families. The mean (SD) age at onset was 37.2 (18.0) years. Familial NMOSD involved 1-2 generations with mainly 2 affected individuals. The most common kinship pattern was siblingship in 21 families (52.5%). Initial syndromes were mostly optic neuritis and transverse myelitis. Serum aquaporin-4 IgG was positive in 79.7% of cases. Median number of relapses was 3 (range 1-26). Median expanded disability status scale in the last visit was 2 (range 0-8). Reported human leukocyte antigens (HLA) alleles shared between familial cases were HLA-A*01 and HLA-DRB1*03.

CONCLUSION

Familial clustering of NMOSD is more common than would be expected in the general population. The demographic, clinical, and outcome profiles of familial cases were not different from sporadic cases. Certain specific HLA haplotypes were shared among familial cases. Our systematic review highlighted complex genetic predisposition to NMOSD.

A novel rare variant of CNPY3 from familial NMOSD impairs the TLR-mediated immune response

Toll-like receptors (TLRs) are a class of proteins that play essential roles in innate and adaptive immune responses. Recently, accumulating evidence has demonstrated that impairments in the TLR signalling pathway contribute to the development and progression of neuroimmune diseases, such as neuromyelitis optica spectrum disorder (NMOSD). However, the cellular and molecular mechanisms are still largely unknown. In this study, we report a novel variant, C52Y, of canopy FGF signalling regulator 3 (CNPY3) from patients with familial NMOSD and demonstrate that this variant shows a stronger interaction with GP96 and TLRs than with wild-type CNPY3. We find that C52Y has dominant negative effects on TLR4 surface expression. Importantly, the TLR4 surface expression level is decreased in RAW264.7 cells infected with the C52Y virus upon LPS stimulation. We further demonstrate that bone marrow-derived macrophages (BMDMs) from CNPY3C52Y/+ transgenic mice secrete less tumour necrosis factor (TNF) and interleukin (IL)-6 than BMDMs from wild-type mice upon stimulation with LPS. These data suggest that impairment of TLR trafficking may contribute to the development of neuroimmune 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.

AQP4-IgG-positive neuromyelitis optica spectrum disorder and temporally detected neoplasms: case report and systematic review

BACKGROUND

An increasing number of reports on associations between neoplasms and neuromyelitis optica spectrum disorder (NMOSD) have been published over the past decade. However, types of neoplasms and temporal relationships have not been widely studied.

OBJECTIVE

To report cases and determine the associations between neoplasms and NMOSD.

METHOD

A retrospective chart review of possible paraneoplastic NMOSD patients at a university hospital was performed. Articles related to "neoplasm" and "NMOSD" were systematically searched and reviewed. We included aquaporin-4 (AQP4)-IgG-seropositive NMOSD patients whose onset of NMOSD and cancer diagnosis or recurrence were within 24 months of one another. Temporal relationship, types of neoplasms involved, treatments, and outcomes of both NMOSD and neoplasms were determined. The subgroup analysis was based on the AQP4 expression of neoplasm histology.

RESULTS

We identified 3 cases (1.3%) from a cohort of 224 AQP4-IgG-seropositive NMOSD at our hospital and retrieved 68 cases from a systematic review, totaling 71 cases of possible paraneoplastic NMOSD. The median age at onset of NMOSD was 55 (IQR 41-64) years. Eighty percent were female. The most frequently identified types of neoplasms were lung and breast, accounting for 21.1% and 18.3%, respectively. The other tumor types were ovarian tumors and hematologic malignancy, both at 12.7%. The most commonly identified tissue histology was adenocarcinoma (52.1%). We also reported the first case of melanoma in an NMOSD patient. Twenty-eight patients (39.4%) were diagnosed with cancer before the onset of NMOSD with a median duration of 9.5 (range 1-24) months. Of those, eight patients had NMOSD after surgical removal of neoplasms, and one patient had NMOSD after radiotherapy of prostate adenocarcinoma. Twenty-three patients (32.4%) had NMOSD before cancer diagnosis by a median of 3 (range 1-24) months, and the rest were diagnosed concurrently during the same admission. Three cases were diagnosed with NMOSD around the time of tumor recurrence. Tumor tissue expressed AQP4 in 82.4%.

CONCLUSION

A small proportion of AQP4-IgG-positive NMOSD is associated with malignancy. In newly diagnosed NMOSD patients without symptoms of neoplasms, screening for age- and risk-appropriate cancer should be recommended, similar to the general population. The occurrence of NMOSD in cancer patients might suggest tumor recurrence.

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.

Associations and Disease-Disease Interactions of COVID-19 with Congenital and Genetic Disorders: A Comprehensive Review

Since December 2019, the COVID-19 pandemic, which originated in Wuhan, China, has resulted in over six million deaths worldwide. Millions of people who survived this SARS-CoV-2 infection show a number of post-COVID complications. Although, the comorbid conditions and post-COVID complexities are to some extent well reviewed and known, the impact of COVID-19 on pre-existing congenital anomalies and genetic diseases are only documented in isolated case reports and case series, so far. In the present review, we analyzed the PubMed indexed literature published between December 2019 and January 2022 to understand this relationship from various points of view, such as susceptibility, severity and heritability. Based on our knowledge, this is the first comprehensive review on COVID-19 and its associations with various congenital anomalies and genetic diseases. According to reported studies, some congenital disorders present high-risk for developing severe COVID-19 since these disorders already include some comorbidities related to the structure and function of the respiratory and cardiovascular systems, leading to severe pneumonia. Other congenital disorders rather cause psychological burdens to patients and are not considered high-risk for the development of severe COVID-19 infection.

NMOSD and MS prevalence in the Indigenous populations of Australia and New Zealand

BACKGROUND

We studied the prevalence of neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) in Indigenous populations of Australia and New Zealand with the aim of assessing potential differences.

METHODS

Cases of possible NMOSD and MS were collected from Australia and New Zealand. Clinical details, MR imaging, and serologic results were used to apply 2015 IPND diagnostic criteria for NMOSD and 2010 McDonald criteria for MS. Frequencies of self-determined ethnic ancestry were calculated for confirmed NMOSD, suspected NMOSD, and MS. Prevalence rates for NMOSD and MS according to ancestry were compared.

RESULTS

There were 75 cases with NMOSD, 89 with suspected NMSOD, and 101 with MS. NMOSD cases were more likely to have Asian, Indigenous, or Other ancestry compared to suspected NMOSD or MS. There were no differences in the clinical phenotype of NMOSD seen in Indigenous compared to European ancestry populations. Per 100,000, the prevalence estimate for NMOSD in people with Māori ancestry was 1.50 (95% CI 0.52-2.49) which was similar to those with Asian ancestry 1.57 (95% CI 1.15-1.98). NMOSD prevalence in Australian Aboriginal and Torres Strait Islander populations was 0.38 (95% CI 0.00-0.80) per 100,000.

CONCLUSION

The prevalence of NMOSD in the Māori population is similar to South East Asian countries, reflecting their historical origins. The prevalence of MS in this group is intermediate between those with South East Asian and European ancestry living in New Zealand. Both NMOSD and particularly MS appear to be uncommon in the Indigenous populations of Australia.

Can Immune Tolerance Be Re-established in Neuromyelitis Optica?

Neuromyelitis optica (NMO) is a chronic inflammatory disease of the central nervous system that primarily affects the optic nerves and spinal cord of patients, and in some instances their brainstem, diencephalon or cerebrum as spectrum disorders (NMOSD). Clinical and basic science knowledge of NMO has dramatically increased over the last two decades and it has changed the perception of the disease as being inevitably disabling or fatal. Nonetheless, there is still no cure for NMO and all the disease-modifying therapies (DMTs) are only partially effective. Furthermore, DMTs are not disease- or antigen-specific and alter all immune responses including those protective against infections and cancer and are often associated with significant adverse reactions. In this review, we discuss the pathogenic mechanisms of NMO as they pertain to its DMTs and immune tolerance. We also examine novel research therapeutic strategies focused on induction of antigen-specific immune tolerance by administrating tolerogenic immune-modifying nanoparticles (TIMP). Development and implementation of immune tolerance-based therapies in NMO is likely to be an important step toward improving the treatment outcomes of the disease. The antigen-specificity of these therapies will likely ameliorate the disease safely and effectively, and will also eliminate the clinical challenges associated with chronic immunosuppressive therapies.

Pain Symptoms in Optic Neuritis

Signs and symptoms of optic neuritis (ON), an autoimmune disorder of the central nervous system (CNS), differ between patients. Pain, which is commonly reported by ON patients, may be the major reason for some patients to visit the clinic. This article reviews the presence of pain related to ON with respect to underlying disorders, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein associated disease (MOGAD). The aim of this review is to provide an overview of pain symptoms in accordance with the context of various pathophysiological explanations, assist in differential diagnosis of ON patients, especially at the onset of disease, and make recommendations to aid physicians make decisions for follow up diagnostic examinations.

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.

Simultaneous new onset of neuromyelitis optica spectrum disorder in identical twins

Objective

To present a case of two identical twins presenting concurrently with symptoms and subsequent initial diagnosis of neuromyelitis optica spectrum disorder (NMOSD).

Methods

Clinical, laboratory and MRI findings for both twins were reviewed and presented here.

Results

Twin A presented with right eye pain and subsequent blurred vision in right eye. MRI of the brain and spine demonstrated pre-chiasmal right optic nerve enhancement and T2 hyperintense lesions in the spinal cord at T7 and T9 levels. Cerebrospinal fluid (CSF) analysis was remarkable for NMO/aquaporin-4 (AQP4) fluorescence-activated cell sorting (FACS) titre of 1:32 and a serum NMO/AQP4-IgG positive titre of 1:10 000. Twin B presented with diplopia. MRI of the brain and spine demonstrated T2 hyperintense lesions in the periventricular cerebral white matter, in the periaqueductal white matter of the pons, in the midbrain and the cervical spinal cord. Neurological examination findings revealed incomplete right trochlear palsy, rotatory nystagmus, an incomplete left internuclear ophthalmoplegia and hyper-reflexia. CSF analysis was remarkable for NMO/AQP4 FACS titre of 1:256 and a serum NMO-IgG positive titre of 1:10 000. Both twins responded well to intravenous steroid therapy. There was no adverse environmental exposure present.

Conclusion

We present an interesting and rare case of identical twins presenting concurrently and for the first time with NMOSD.

[Epidemiology of neuromyelitis optica spectrum disorder]

Neuromyelitis optica spectrum disorder (NMOSD) is a group of rare and mostly severe autoimmune demyelinating central nervous system disorders which prevalence is 0.7-1 per 100.000 population and incidence is 0.037-0.73 per 100.000 person-years. NMOSD may present as a combination of uni- or bilateral optic neuritis, transverse myelitis or lesions of brain stem and other brain regions. The symptoms are mostly relapsing (up to 97.5%) and progressive. Occurrence of relapses is associated with seropositivity for aquaporin-4 (up to 80% of NMOSD patients) and bears a less favorable prognosis (mortality up to 32%). Women seropositive for aquaporin 4 constitute 90% of NMOSD patients. Compared to other demyelinating disorders, NMOSD is characterized by late onset (mean age is about 39 years) and association with other autoimmune disorders, including systemic lupus erythematosus, myasthenia gravis and Sjogren's syndrome. A genetic predisposition was found among Blacks and Asians, with HLA-DRB1*03:01 gene associated with higher risk of NMOSD in Asians. The course of the disease tends to be more severe in Blacks. There are clusters of an increased incidence of NMOSD in the Carribeans and in the Far East. Continued increase of prevalence and incidence of NMOSD worldwide compels continued epidemiological research in order to provide early diagnosis and treatment for this disorder.

Recent Advances in Neuromyelitis Optica Spectrum Disorder: Pathogenesis, Mechanisms and Potential Treatments

Neuromyelitis optica spectrum disorder (NMOSD) is an acute or subacute demyelinating disease that affects mainly the optic nerve and spinal cord. A major proportion of NMOSD cases have a relationship with autoimmunity to aquaporin 4 (AQP4) found on the central nervous system. NMOSD can occur repeatedly, causing symptoms such as decreased vision and weakness of limbs. The main goal of current therapy is to relieve acute symptoms and prevent recurrence of the disease. Without timely and appropriate treatment, the recurrence and disability rates are high. In the present work, we review recent advances in the diagnosis and treatment of patients with NMOSD, as well as the pathogenesis and mechanisms of AQP4-IgG-seropositive NMOSD.

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

BACKGROUND AND OBJECTIVE

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease. Although genetic factors are involved in its pathogenesis, limited evidence is available in this area. The aim of the present study was to identify the major genetic factors contributing to NMOSD in Chinese patients with aquaporin 4 (AQP4)-IgG seropositivity.

METHODS

Whole-exome sequencing (WES) was performed on 228 Chinese NMOSD patients seropositive for AQP4-IgG and 1400 healthy controls in Guangzhou, South China. Human leukocyte antigen (HLA) sequencing was also utilized. Genotype model and haplotype, gene burden, and enrichment analyses were conducted.

RESULTS

A significant region of the HLA composition is on chromosome 6, and great variation was observed in DQB1, DQA2 and DQA1. HLA sequencing confirmed that the most significant allele was HLA-DQB1*05:02 (p < 0.01, odds ratio [OR] 3.73). The genotype model analysis revealed that HLA-DQB1*05:02 was significantly associated with NMOSD in the additive effect model and dominant effect model (p < 0.05). The proportion of haplotype "HLA-DQB1*05:02-DRB1*15:01" was significantly greater in the NMOSD patients than the controls, at 8.42% and 1.23%, respectively (p < 0.001, OR 7.39). The gene burden analysis demonstrated that loss-of-function mutations in NOP16 were more common in the NMOSD patients (11.84%) than the controls (5.71%; p < 0.001, OR 2.22). The IgG1-G390R variant was significantly more common in NMOSD, and the rate of the T allele was 0.605 in patients and 0.345 in the controls (p < 0.01, OR 2.92). The enrichment analysis indicated that most of the genetic factors were mainly correlated with nervous and immune processes.

CONCLUSIONS

Human leukocyte antigen is highly correlated with NMOSD. NOP16 and IgG1-G390R play important roles in disease susceptibility.

Neuromyelitis optica is an HLA associated disease different from Multiple Sclerosis: a systematic review with meta-analysis

Neuromyelitis Optica and Multiple Sclerosis are idiopathic inflammatory demyelinating diseases of the central nervous system that currently are considered distinct autoimmune diseases, so differences in genetic susceptibility would be expected. This study aimed to investigate the HLA association with Neuromyelitis Optica by a systematic review with meta-analysis. The STROBE instrument guided research paper assessments. Thirteen papers published between 2009 and 2020 were eligible. 568 Neuromyelitis Optica patients, 41.4% Asians, 32.4% Latin Americans and 26.2% Europeans were analyzed. Only alleles of the DRB1 locus were genotyped in all studies. Neuromyelitis Optica patients have 2.46 more chances of having the DRB1*03 allelic group than controls. Ethnicity can influence genetic susceptibility. The main HLA association with Neuromyelitis Optica was the DRB1*03:01 allele in Western populations and with the DPB1*05:01 allele in Asia. Differences in the Multiple Sclerosis and Neuromyelitis Optica genetic susceptibility was confirmed in Afro descendants. The DRB1*03 allelic group associated with Neuromyelitis Optica has also been described in other systemic autoimmune diseases.

Worldwide Incidence and Prevalence of Neuromyelitis Optica: A Systematic Review

Objective

Since the last epidemiologic review of neuromyelitis optica/neuromyelitis optica spectrum disorder (NMO/NMOSD), 22 additional studies have been conducted. We systematically review the worldwide prevalence, incidence, and basic demographic characteristics of NMOSD and provide a critical overview of studies.

Methods

PubMed, Ovid MEDLINE, and Embase using Medical Subject Headings and keyword search terms and reference lists of retrieved articles were searched from 1999 until August 2019. We collected data on the country; region; methods of case assessment and aquaporin-4 antibody (AQP4-Ab) test; study period; limitations; incidence (per 100,000 person-years); prevalence (per 100,000 persons); and age-, sex-, and ethnic group–specific incidence or prevalence.

Results

We identified 33 relevant articles. The results indicated the highest estimates of incidence and prevalence of NMOSD in Afro-Caribbean region (0.73/100 000 person-years [95% CI: 0.45–1.01] and 10/100 000 persons [95% CI: 6.8–13.2]). The lowest incidence and prevalence of NMOSD were found in Australia and New Zealand (0.037/100 000 person-years [95% CI: 0.036–0.038] and 0.7/100,000 persons [95% CI: 0.66–0.74]). There was prominent female predominance in adults and the AQP4-Ab–seropositive subpopulation. The incidence and prevalence peaked in middle-aged adults. African ethnicity had the highest incidence and prevalence of NMOSD, whereas White ethnicity had the lowest. No remarkable trend of incidence was described over time.

Conclusion

NMOSD is a rare disease worldwide. Variations in prevalence and incidence have been described among different geographic areas and ethnicities. These are only partially explained by different study methods and NMO/NMOSD definitions, highlighting the need for specifically designed epidemiologic studies to identify genetic effects and etiologic factors.

Neuromyelitis optica spectrum disorders

The disease concept of Neuromyelitis Optica Spectrum Disorders(NMOSD) has undergone a significant change over the last two decades including the detection of Myelin Oligodendrocyte Glycoprotein(MOG) antibody in patients who are seronegative for aquaporin-4 antibody. Aquaporin-4 antibody positive NMOSD is now regarded as an immune astrocytopathy. Conversely, MOG antibody associated disease is known to target myelin rather than astrocytes, leading to an NMOSD syndrome with distinct clinical and radiological features. Incorporation of clinical features like area postrema syndrome, brainstem syndrome, diencephalic syndrome and cortical manifestations as core clinical characteristics into the revised diagnostic criteria has widened the clinical spectrum of NMOSD. With the development of these criteria, it is possible to make the diagnosis at an earlier stage so that effective immunosuppression can be instituted promptly for a better long-term prognosis. Newer therapeutic agents have been introduced for aquaporin-4 seropositive NMOSD disease; however, challenges remain in treating seronegative disease because of limited treatment options.

Common genetic variants in PRRC2A are associated with both neuromyelitis optica spectrum disorder and multiple sclerosis in Han Chinese population

BACKGROUND

The proline-rich coiled-coil 2A (PRRC2A) gene has been reported to underlie risk of various autoimmune diseases. However, no data reveal the risk susceptibility of PRRC2A to neuromyelitis optica spectrum disorder (NMOSD) and multiple sclerosis (MS) so far.

OBJECTIVES

To explore the association between PRRC2A variants and NMOSD and MS susceptibility in Han Chinese population.

METHODS

Totally, 207 NMOSD (98 AQP4⁺ and 109 AQP4^-) patients, 141 MS and 196 healthy controls (HC) were enrolled. Candidate tagging single nucleotide polymorphisms (tag-SNPs) were selected from the 1000G database based on the Chinese data. SNP genotyping was performed using MassArray and Sanger sequencing.

RESULTS

PRRC2A variants rs2736171, rs2736157, rs2844470 alter susceptibility to AQP4⁺ NMOSD, while rs2242659 to MS. Genotype AT of rs2844470 and AG of rs2242659 increased risk susceptibility for AQP4⁺ NMOSD and MS, respectively. AQP4⁺ NMOSD exhibited a higher frequency of genotype AG of rs2736157 compared with AQP4^- NMOSD. Haplotype TCAAGGTAG was conferred risk susceptibility to AQP4⁺ NMOSD and haplotype TTAGAGTAG had a protective effect on both AQP4⁺ and AQP4^- NMOSD. Further, we identified various gene expression levels in disease-related regions that are significantly modulated by three cis-eQTL SNPs rs2736157, rs2736171 and rs2242659 (p < 1.05 × 10^-4).

CONCLUSIONS

PRRC2A variants are first reported to be associated with NMOSD and MS. The identified PRRC2A variants may shed light on the pathogenesis of NMOSD and MS and potentially lead to an individualized therapeutic approach for both distinct disease entities.

Hematopoietic Stem Cell Transplantation in Neuromyelitis Optica-Spectrum Disorders (NMO-SD): State-of-the-Art and Future Perspectives

Neuromyelitis optica (NMO) and neuromyelitis optica spectrum disorders (NMOSD) are a group of autoimmune inflammatory disorders of the central nervous system (CNS). Understanding of the molecular basis of these diseases in the last decades has led to an important improvement in the treatment of this disease, in particular, to the use of immunotherapeutic approaches, such as monoclonal antibodies and Hematopoietic Stem Cell Transplantation (HSCT). The aim of this review is to summarize the pathogenesis, biological basis and new treatment options of these disorders, with a particular focus on HSCT applications. Different HSCT strategies are being explored in NMOSD, both autologous and allogeneic HSCT, with the new emergence of therapeutic effects such as an induction of tolerance to auto-antigens and graft versus autoimmunity effects that can be exploited to hopefully treat a disease that still has prognosis.

Familial clustering of neuromyelitis optica and multiple sclerosis: clues pointing towards shared risks?

We examine the prevalence of the familial association of concordant NMOSD/NMOSD and discordant NMOSD/MS cases among a large NMOSD cohort. Familial association was examined in a monocenter cohort of 119 NMOSD patients and 45 patients at high risk of NMOSD from French West Indies. Data mining gathered 31 multiplex families. Twin monozygotic sisters concordant for NMOSD/NMOSD, and four discordant NMOSD/MS families, accounted respectively for 0.8% and 3.4% of the NMOSD cohort. Familial clustering was more frequent than random association. In discordant NMOSD/MS families, the NMOSD patient was always from the parental generation. The non-random successive familial cases of NMOSD and MS suggest a change of risk factor over generations.

Association Between BDNF Val66Met Polymorphism and Optic Neuritis Damage in Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system (CNS). The purpose of the study was to examine the association between the brain-derived neurotrophic factor (BDNF) Val66Met genotype and structural and functional optic nerve damage in the eyes of NMOSD patients. A total of 17 NMOSD subjects (34 eyes) were included in the study and were divided into subgroups based on optic neuritis (ON) history and BDNF Val66Met polymorphisms. The mean (range) age was 47.8 (23–78) years, and the mean (SD) disease duration was 7.4 (2–39) years. All participants had undergone optical coherence tomography (OCT) scans for global retinal nerve fiber layer (gRNFL) and ganglion cell-inner plexiform layer (GCIPL) thickness and multifocal visual evoked potential (mfVEP) test for amplitude and latency. BDNF Val66Met polymorphisms were genotyped in all participants. OCT and mfVEP changes were compared between two genotype groups (Met carriers vs. Val homozygotes) by using the generalised estimating equation (GEE) models. The BDNF Val66Met polymorphism was significantly associated with more severe nerve fiber layer damage and axonal loss in ON eyes of NMOSD subjects. Met carriers had more significantly reduced GCIPL (P = 0.002) and gRNFL (P < 0.001) thickness as well as more delayed mfVEP latency (P = 0.008) in ON eyes. No association was found between Val66Met variants and non-ON (NON)-eye of the participants. These findings suggest that the BDNF Val66Met polymorphism may be associated with optic nerve damage caused by acute ON attacks in NMOSD patients.

Neuromyelitis Optica Spectrum Disorder and Anti-MOG Syndromes

Neuromyelitis optica spectrum disorder (NMOSD) and anti-myelin oligodendrocyte glycoprotein (anti-MOG) syndromes are immune-mediated inflammatory conditions of the central nervous system that frequently involve the optic nerves and the spinal cord. Because of their similar clinical manifestations and habitual relapsing course they are frequently confounded with multiple sclerosis (MS). Early and accurate diagnosis of these distinct conditions is relevant as they have different treatments. Some agents used for MS treatment may be deleterious to NMOSD. NMOSD is frequently associated with antibodies which target aquaporin-4 (AQP4), the most abundant water channel in the CNS, located in the astrocytic processes at the blood-brain barrier (BBB). On the other hand, anti-MOG syndromes result from damage to myelin oligodendrocyte glycoprotein (MOG), expressed on surfaces of oligodendrocytes and myelin sheaths. Acute transverse myelitis with longitudinally extensive lesion on spinal MRI is the most frequent inaugural manifestation of NMOSD, usually followed by optic neuritis. Other core clinical characteristics include area postrema syndrome, brainstem, diencephalic and cerebral symptoms that may be associated with typical MRI abnormalities. Acute disseminated encephalomyelitis and bilateral or recurrent optic neuritis are the most frequent anti-MOG syndromes in children and adults, respectively. Attacks are usually treated with steroids, and relapses prevention with immunosuppressive drugs. Promising emerging therapies for NMOSD include monoclonal antibodies and tolerization.

Neuromyelitis optica spectrum disorder in three generations of a Chinese family

Neuromyelitis optica spectrum disorder is an inflammatory demyelinating disease that is largely sporadic. Familial disease has been reported in one or two generations, although its basis remains unknown. We report here three subjects meeting diagnostic criteria for NMOSD in one family: a father and son, and the maternal aunt of the father. Anticipation, of 27 years, was apparent in transmission from father to son. Aquaporin-4 antibodies were observed in the aunt but not the father and son, nor in other family members. A putative pathogenic mutation in the NECL2 gene was not found in this pedigree. This first report of NMOSD in three generations of one family underlines the heterogeneity of familial NMOSD.

Neuromyelitis optica spectrum disorders

Neuromyelitis optica spectrum disorder (NMOSD) is an uncommon antibody-mediated disease of the central nervous system. Long segments of spinal cord inflammation (myelitis), severe optic neuritis, and/or bouts of intractable vomiting and hiccoughs (area postrema syndrome) are classic presentations of the disease and may alert the clinician to the diagnosis. Untreated, approximately 50% of NMOSD patients will be wheelchair users and blind, and a third will have died within 5 years of their first attack. Unlike multiple sclerosis, a progressive clinical course is very unusual and the accrual of disability is related to relapses. Approximately 75% of patients have antibodies against aquaporin-4, a water channel expressed on astrocytes. Relapses are treated aggressively to prevent residual disability with high-dose steroids and often plasma exchange. Relapse prevention is crucial and achieved with long-term immunosuppression. In this article we review the pathogenesis, clinical features, diagnosis and management of NMOSD.

NEUROMYELITIS OPTICA SPECTRUM DISORDERS: DIAGNOSIS AND TREATMENT, THE EXPERIENCE OF CLINICAL OBSERVATIONS

Neuromyelitis optica spectrum disorder (NMOSD) is an aggregate of inflammatory and autoimmune disorders of the central nervous system characterized by recurrent, disabling clinical course and damages predominantly targeting optic nerves, brain stem and spinal cord. NMOSD is stratified into two types: seropositive for aquaporin-4 antibodies (AQP4-IgG) and seronegative, which is reported in 25 % of cases. This article presents modern conceptualizations of NMOSD and describes authors’ own experience of clinical observation of patients.

Detection of aquaporin-4 antibodies for patients with CNS inflammatory demyelinating diseases other than typical MS in Lithuania

OBJECTIVES

Neuromyelitis optica (NMO) is frequently associated with aquaporin-4 autoantibodies (AQP4-Ab); however, studies of NMO in Lithuania are lacking. Therefore, the main objective of our study is to assess positivity for AQP4-Ab in patients presenting with inflammatory demyelinating central nervous system (CNS) diseases other than typical multiple sclerosis (MS) in Lithuania.

MATERIALS AND METHODS

Data were collected from the two largest University hospitals in Lithuania. During the study period, there were 121 newly diagnosed typical MS cases, which were included in the MS registry database. After excluding these typical MS cases, we analyzed the remaining 29 cases of other CNS inflammatory demyelinating diseases, including atypical MS (n = 14), acute transverse myelitis, TM (n = 8), acute disseminated encephalomyelitis, ADEM (n = 3), clinically isolated syndrome, CIS (n = 2), atypical optic neuritis, ON (n = 1), and NMO (n = 1). We assessed positivity for AQP4-Ab for the 29 patients and evaluated clinical, laboratory, and instrumental differences between AQP4-Ab seropositive and AQP4-Ab seronegative patient groups.

RESULTS

AQP4-Ab test was positive for three (10.3%) patients in our study, with initial diagnoses of atypical MS (n = 2) and ADEM (n = 1). One study patient was AQP4-Ab negative despite being previously clinically diagnosed with NMO. There were no significant clinical, laboratory, or instrumental differences between the groups of AQP4-Ab positive (3 [10.3%]) and negative (26 [89.7%]) patients.

CONCLUSIONS

AQP4-Ab test was positive for one-tenth of patients with CNS inflammatory demyelinating diseases other than typical MS in our study. AQP4-Ab testing is highly recommended for patients presenting with not only TM and ON but also an atypical course of MS and ADEM.

Reduced expression of the IL7Ra signaling pathway in Neuromyelitis optica

Neuromyelitis optica (NMO) is a chronic inflammatory demyelinating autoimmune disease of the central nervous system that most commonly affects the optic nerves and spinal cord. To characterize the immunological pathways involved in NMO, whole blood RNA expression array was performed using Nanostring nCounter technology. Two major clusters of genes were found associated with NMO: T cell-associated genes and the TNF/NF-kB signaling pathway. Analysis of the genes within the first cluster confirmed significantly reduced expression of IL7Ra (CD127) in the peripheral blood of NMO patients vs that in healthy controls. IL7Ra upstream transcription factors and its downstream survival signaling pathway were also markedly reduced. In line with the essential role of IL7Ra in T cell maturation and survival, a significantly lower number of naïve T cells, and reduced T cell survival signaling mediated by increased BID (BH3-interacting domain death agonist) expression and increased apoptosis was observed. Cumulatively, these findings indicate that the IL7Ra signaling pathway may play a role in the autoimmune process in NMO.

Diagnosis and management of neuromyelitis optica spectrum disorders - An update

Neuromyelitis optica (NMO) and Neuromyelitis optica spectrum disorders (NMOSD) are a group of autoimmune conditions characterized by inflammatory involvement of the optic nerve, spinal cord and central nervous system. Novel evidence showed a key role of autoantibodies against aquaporin-4 immunoglobulin G (AQP4 IgG) in the pathogenesis of NMOSD and, recently, new classification and diagnostic criteria have been adopted to facilitate an earlier identification and improve the management of these conditions. Diagnosis of NMOSD is currently based on clinical, neuroimaging and laboratory features. Standard treatment is based on the use of steroids and immunosuppressive drugs and aims to control the severity of acute attacks and to prevent relapses of the disease. This review gives an update of latest knowledge of NMOSD and NMO, emphasizing the novel diagnostic criteria and both current and future therapeutic approaches.

Immunopathogenesis in Myasthenia Gravis and Neuromyelitis Optica

Myasthenia gravis (MG) and neuromyelitis optica (NMO) are autoimmune channelopathies of the peripheral neuromuscular junction (NMJ) and central nervous system (CNS) that are mainly mediated by humoral immunity against the acetylcholine receptor (AChR) and aquaporin-4 (AQP4), respectively. The diseases share some common features, including genetic predispositions, environmental factors, the breakdown of tolerance, the collaboration of T cells and B cells, imbalances in T helper 1 (Th1)/Th2/Th17/regulatory T cells, aberrant cytokine and antibody secretion, and complement system activation. However, some aspects of the immune mechanisms are unique. Both targets (AChR and AQP4) are expressed in the periphery and CNS, but MG mainly affects the NMJ in the periphery outside of CNS, whereas NMO preferentially involves the CNS. Inflammatory cells, including B cells and macrophages, often infiltrate the thymus but not the target—muscle in MG, whereas the infiltration of inflammatory cells, mainly polymorphonuclear leukocytes and macrophages, in NMO, is always observed in the target organ—the spinal cord. A review of the common and discrepant characteristics of these two autoimmune channelopathies may expand our understanding of the pathogenic mechanism of both disorders and assist in the development of proper treatments in the future.

Multiplex family with GAD65-Abs neurologic syndromes

Objective:

Neurologic autoimmune syndromes associated with anti–glutamate acid decarboxylase 65 antibodies (GAD65-Abs) are rare and mostly sporadic.

Methods:

We describe a niece and her aunt with GAD65-Abs neurologic syndromes. High-resolution HLA typing of Class I and Class II alleles was performed using next-generation sequencing.

Results:

The proband had cerebellar ataxia and probable limbic encephalitis features, whereas her niece had stiff-person syndrome. Both had a high titer of GAD65-Abs in serum and CSF and showed signs of inflammation in CSF. Both affected members carried the same rare recombinant DRB1*15:01:01∼DQA1*01:02:01∼DQB1*05:02:01 haplotype, which may or may not be involved in disease susceptibility. Of interest, other unaffected members of the family either had the same HLA haplotype but normal serum GAD65-Abs or had different HLA types but a high titer of serum GAD65-Abs without neurologic symptoms, suggesting cumulative effects.

Conclusions:

This unique association strengthens the concept that hereditary factors, possibly including specific HLA haplotypes, play a role in neurologic syndromes associated with GAD65-Abs.