Leigh syndrome mimicking neuromyelitis optica spectrum disorder (NMOSD).

We report two children with molecularly confirmed mitochondrial disease mimicking Neuromyelitis Optica Spectrum Disorder (NMOSD). The first patient presented at the age of 15 months with acute deterioration following a pyrexial illness with clinical features localising to the brainstem and spinal cord. The second patient presented at 5 years with acute bilateral visual loss. In both cases, MOG and AQP4 antibodies were negative. Both patients died within a year of symptoms onset from respiratory failure. Arriving at an early genetic diagnosis is important for redirection of care and avoiding potentially harmful immunosuppressant therapies.

Two rare cases of myelin oligodendrocyte glycoprotein antibody-associated disorder in children with leukodystrophy-like imaging findings.

BACKGROUND: Children with acquired demyelinating syndromes (ADS) whose sera are positive for myelin oligodendrocyte glycoprotein (MOG) immunoglobulin (IgG) can be diagnosed with MOG-IgG associated disorder (MOGAD). Cases with leukodystrophy-like imaging findings with recurrent MOGAD have rarely been reported. CASE PRESENTATION: Two children with MOGAD, whose onset age was 6 months and 3 years, respectively, were admitted to the hospital due to fever and altered consciousness. In both children, MOG-IgG was detected in the serum using live cell-based assay. Brain magnetic resonance imaging (MRI) revealed leukodystrophy-like lesions with diffuse bilateral white matter. Cerebrospinal fluid (CSF) analysis showed mild pleocytosis with normal or slightly increased protein levels and no oligoclonal bands. Metabolic and inflammatory blood/CSF markers were all negative. Full exon gene testing revealed normal results, and nuclear and mitochondrial DNA were normal. Despite regular immunotherapy and reduction of lesions based on brain MRI results, the patients repeatedly relapsed and had residual neurological dysfunction at 3-4 years of follow-up. CONCLUSIONS: Although MOGAD is a monophasic and benign condition, certain MOGAD patients can experience multiple relapses and residual neurologic deficits. The spectrum of clinical manifestations in MOGAD is wider in children than in previously reported cases, including cases with leukodystrophy-like imaging findings. Such imaging findings along with MOG-IgG may occur recurrently and result in severe neurological prognosis. Patients with extensive and confluent white matter lesions should undergo early testing of MOG-IgG to ensure early therapy. In refractory cases, MOGAD treatment may need to be escalated beyond the current therapy, which means second-line immunotherapy should be performed as early as possible and hormone levels should not be rapidly reduced. Early diagnosis and appropriate treatment may improve the prognosis of children with MOGAD.

Clinical characteristics and prognosis of pediatric myelin oligodendrocyte glycoprotein antibody-associated diseases in China.

BACKGROUND: Research on myelin oligodendrocyte glycoprotein antibody (MOG-Ab)-associated disease (MOGAD) among Chinese children is relatively rare. Therefore, this study aimed to explore and analyze the clinical characteristics and prognoses of Chinese children with acquired demyelinating syndromes (ADSs) who tested positive or negative for MOG-Ab. METHODS: The clinical data of children with MOGAD who were treated in the Department of Neurology at Shanghai Children's Hospital from January 2017 to October 2021 were retrospectively collected. RESULTS: Among 90 children with ADSs, 30 were MOG-Ab-positive, and 60 were MOG-Ab-negative. MOG-Ab-positive children experienced more prodromal infections than did MOG-Ab-negative children (P < 0.05). Acute disseminated encephalomyelitis was the most common ADSs in both groups. There were ten cases of a rebound increase in MOG-Ab titers. There were significant differences in the MOG titer-related prognosis and disease time course between the disease relapse group and the non-relapse group (P < 0.01). Among the MOG-Ab-positive patients, the most affected brain areas detected via magnetic resonance imaging (MRI) were the temporal lobe, cerebellar hemispheres, brainstem, and periventricular lesions. The most common shapes of the lesions were commas, triangles, or patches. The average improvement time based on brain MRI was much longer in MOG-Ab-positive than in MOG-Ab-negative children (P < 0.05). The initial treatment time correlated with the disease time course, and the prognosis may be affected by the disease time course and serum MOG-Ab titer (P < 0.05). CONCLUSION: The clinical characteristics and imaging features of ADSs differed between MOG-Ab-positive and MOG-Ab-negative children. In addition to existing treatment plans, additional diagnoses and treatment plans should be developed to reduce recurrence and improve the prognoses of children with MOGAD.

Utility of paramagnetic rim lesions on 1.5-T susceptibility phase imaging for the diagnosis of pediatric multiple sclerosis.

BACKGROUND: Studies have suggested that paramagnetic rim lesions on 7-tesla (T) and 3-T susceptibility-based brain MRI are specific features of multiple sclerosis (MS) lesions in adults. OBJECTIVE: The aim of this study was to investigate whether the presence of paramagnetic rim lesions on 1.5-T phase images can help discriminate pediatric patients with MS from those with other demyelinating diseases. MATERIALS AND METHODS: In this retrospective study we reviewed brain MRIs performed on 1.5-T scanners that included susceptibility-weighted imaging (SWI) sequences with phase images in children younger than 18 years diagnosed with MS and other acquired demyelinating syndromes. In each case, five white matter lesions were selected using T2/fluid-attenuated inversion recovery images for further paramagnetic rim evaluation on SWI. Two researchers performed independent assessments of the presence of paramagnetic rim lesions. Discrepancies between them were settled by consensus, with input from a senior neuroradiologist. RESULTS: We included 13 children diagnosed with MS and 16 children diagnosed with non-MS demyelinating diseases and analyzed a total of 132 focal white matter lesions. Seventy-one percent of the lesions in the MS group had paramagnetic rims, while none of the lesions in the non-MS group had rims. All but one of the children with MS had at least one lesion with a paramagnetic rim. The presence of one lesion with a paramagnetic rim on 1.5-T phase-contrast images resulted in 70% sensitivity and 100% specificity for MS. CONCLUSION: Paramagnetic rim lesions detected on 1.5-T phase-contrast MR images can help discriminate MS from other acquired demyelinating syndromes in the pediatric population.

The clinical spectrum and incidence of anti-MOG-associated acquired demyelinating syndromes in children and adults.

OBJECTIVES: The aim of this study was to assess the Dutch nationwide incidence of myelin oligodendrocyte glycoprotein (MOG)-IgG-associated acquired demyelinating syndromes (ADS) and to describe the clinical and serological characteristics of these patients. METHODS: All serum samples for routine diagnostics from February 2014 to December 2017 were sent to the single central reference laboratory for the full-length MOG-IgG cell-based assay (CBA) in the Netherlands. Clinical data from patients known in our National ADS centre were available. RESULTS: A total of 1414 samples of 1277 patients were received; of these, 92 patients (7%) were MOG-IgG-seropositive. The mean incidence was 0.16/100,000 people, with higher seropositivity in children (0.31/100,000) than in adults (0.13/100,000). In MOG-IgG-positive patients at the National ADS centre (61/92, 66%), the most common presenting phenotype is acute disseminated encephalomyelitis (ADEM, 56%) in children and optic neuritis (ON, 44%) in adults. Relapsing disease occurred in 9/34 (26%) children and 11/27 (41%) adults during median follow-up of 27.5 months. Patients were tested MOG-IgG-positive >200 months after the initial attack, suggesting an extended time to first relapse (TTFR). Longitudinal analysis of MOG-IgG (25/61, 41%) showed that 67% of the monophasic patients remain seropositive and 60% in relapsing patients. Majority of seronegative patients had no relapses (89%). CONCLUSION: This nationwide study shows that the overall incidence of MOG-IgG-seropositive disorders is 0.16 per 100,000 people. The distribution over the clinical phenotypes differs between adults and children. Seropositivity can be maintained over years even without clinical activity, while seronegative patients generally had no relapses.

T-cell activation marker sCD27 is associated with clinically definite multiple sclerosis in childhood-acquired demyelinating syndromes.

BACKGROUND: Cerebrospinal fluid (CSF) levels of T-cell activation marker soluble CD27 (sCD27) are associated with subsequent disease activity after a first attack of suspected MS in adults. The predictive value for disease course in children with acquired demyelinating syndromes (ADS) is unknown. OBJECTIVES: To assess the predictive value of sCD27 levels for clinically definite multiple sclerosis (CDMS) diagnosis in childhood ADS. METHODS: Children <18 years with a first demyelinating event were prospectively included and followed. Soluble CD27 was determined in CSF using an enzyme-linked immunosorbent assay (ELISA). Cox regression analyses were used to calculate hazard ratios (HRs) for CDMS. RESULTS: A total of 94 ADS children were included (ADS with encephalopathy (ADS+) n = 33 and ADS without encephalopathy (ADS-) n = 61). Of the 61 ADS- children, 21 (48%) were diagnosed with CDMS during follow-up. At baseline, sCD27 levels were higher in patients with a future CDMS diagnosis ( n = 29) than in monophasic ADS+ ( n = 30), monophasic ADS- ( n = 28) and relapsing non-MS patients ( n = 7; p < 0.001). In ADS- patients, sCD27 was associated with CDMS (HR = 1.8 per 100 U/mL increase in sCD27 levels, p = 0.031), after adjustments for age, oligoclonal bands and the presence of dissemination in space on baseline magnetic resonance imaging (MRI). CONCLUSION: CSF sCD27 levels at first attack of demyelination were associated with CDMS diagnosis in children. This makes sCD27 a potential clinically relevant quantitative marker when performing routine CSF diagnostics.

Children with multiphasic disseminated encephalomyelitis and antibodies to the myelin oligodendrocyte glycoprotein (MOG): Extending the spectrum of MOG antibody positive diseases.

BACKGROUND: Myelin oligodendrocyte glycoprotein (MOG) antibodies have been described in children with acute disseminated encephalomyelitis (ADEM), recurrent optic neuritis, neuromyelitis optica spectrum disorders and more recently in children with multiphasic disseminated encephalomyelitis (MDEM). OBJECTIVE: To delineate the clinical, cerebrospinal fluid (CSF) and radiological features of paediatric MDEM with MOG antibodies. METHODS: Clinical course, serum antibodies, CSF, magnetic resonance imaging (MRI) studies and outcome of paediatric MDEM patients were reviewed. RESULTS: A total of 8 children with two or more episodes of ADEM were identified from a cohort of 295 children with acute demyelinating events. All children had persisting MOG antibodies (median titre: 1:1280). All ADEM episodes included encephalopathy, polyfocal neurological signs and a typical MRI. Apart from ADEM episodes, three children had further clinical attacks without encephalopathy. Median age at initial presentation was 3 years (range: 1-7 years) and median follow-up 4 years (range: 1-8 years). New ADEM episodes were associated with new neurological signs and new MRI lesions. Clinical outcome did range from normal (four of the eight) to mild or moderate impairment (four of the eight). A total of four children received monthly immunoglobulin treatment during the disease course. CONCLUSION: Children with MDEM and persisting MOG antibodies constitute a distinct entity of relapsing demyelinating events and extend the spectrum of MOG antibody-associated diseases.

Anti-MOG antibodies plead against MS diagnosis in an Acquired Demyelinating Syndromes cohort.

BACKGROUND: Acquired demyelinating syndromes (ADS) in children are a group of distinct first immune-mediated demyelinating events of the central nervous system (CNS). Predictive biomarkers for future diagnosis are lacking. A putative target antigen is myelin oligodendrocyte glycoprotein (MOG). We analyzed the presence of MOG antibodies in a cohort of ADS patients in The Netherlands. METHODS: Using a cell-based assay, we analyzed 117 children with ADS from a nationwide cohort, whom were divided into five groups: optic neuritis (ON; n = 20), transverse myelitis (TM; n = 7), other monofocal ADS (n = 22), polyfocal ADS without encephalopathy (n = 44) and polyfocal ADS with encephalopathy (n = 24). Additionally, we tested children with other neurological diseases (OND; n = 13), healthy children (n = 31) and adult polyfocal ADS plus encephalopathy (ADEM) patients (n = 29). RESULTS: We found that 21 of the 117 children with ADS tested anti-MOG seropositive (18%). The group of patients with ADEM had the highest prevalence of anti-MOG seropositivity (42% versus 18% in the non-encephalopathic polyfocal ADS patients). Although 47 ADS children had a final diagnosis of multiple sclerosis (MS), in only one of them were MOG antibodies detected (2%), with only borderline positivity. Only 1 out of the 29 adult ADEM patients tested anti-MOG seropositive. CONCLUSIONS: MOG antibodies are strongly skewed towards ADS children that present with an ADEM-like disease onset. The presence of such antibodies pleads against a future diagnosis of MS.

Encephalitis is an Important Phenotype of Myelin Oligodendrocyte Glycoprotein Antibody-Associated Diseases: A Single-Center Cohort Study.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is considered a demyelinating disease of the central nervous system, but an increasing number of encephalitis cases associated with MOG antibodies have been reported recently. METHODS: This was a single-center, retrospective study. All data for pediatric patients with MOGAD diagnosed at Beijing Children's Hospital from January 2017 to January 2022 were collected. Clinical characteristics and outcomes were analyzed, and treatment responses were compared between the rituximab (RTX) and mycophenolate mofetil (MMF) groups. RESULTS: A total of 190 patients (age range: 5 months to 16 years; median age: 7.2 years; females: 97) were included in this study. The phenotypes of the first attack included acquired demyelinating syndromes (105 [55%]), encephalitis other than acute disseminated encephalomyelitis (82 [43%]), and isolated meningitis (3 [2%]). After a median follow-up of 30.4 months (interquartile range: 14.8-43.7), 64 (34%) patients had relapses. Fifty-one of the 64 (80%) patients who had relapse received maintenance therapy, including MMF (41), RTX (11), maintenance intravenous immunoglobulin (two), and tocilizumab (two). The annualized relapse rates decreased significantly after treatment in both the RTX and MMF cohorts (P < 0.05); however, there were no significant differences between the two groups (P = 0.56). A total of 178 (94%) patients had complete (175 patients) or almost complete (three patients) recovery (modified Rankin scale [mRS] < 2), and 12 had moderate to severe deficits (mRS ≥ 2). CONCLUSIONS: The spectrum of pediatric MOGAD is broader than previously reported and includes demyelinating syndromes and encephalitis. Encephalitis is an important initial phenotype observed in pediatric patients with MOGAD.

Long term outcome in non-multiple sclerosis paediatric acquired demyelinating syndromes.

OBJECTIVES: We aimed to study the risks of relapse and long term disability in children with non-MS acquired demyelinating syndromes (ADS). METHODS: In this prospective, multi-centre study, from the 14 UK pediatric neurology centres, children (<16 years) experiencing a first episode of ADS were recruited from 2010 to 2014. Case report forms were collected prospectively. RESULTS: A total of 269 children were recruited and followed up for a median of 7.2 years. Median age at onset was 9y (IQR 9.5-14.5, 126 females). At last follow-up, 46 (18 %) had MS, 4 AQP4-Ab NMOSD and 206 (80 %) had other ADS, of which 27 (13 %) relapsed. Relapsing MOGAD was the diagnosis in 12/27, 6 were seronegative and 9 did not have antibodies tested. Frequency of relapse differed according to first presentation in non-MS ADS, being least likely in transverse myelitis (p = 0.025). In the non-MS group, MOG-Ab was predictive of relapse (HR = 8.42; p < 0.001) occurring 8 times as often decreasing over time. Long-term difficulties did not differ between children with monophasic vs relapsing diseases. CONCLUSION: The risk of relapse in non-MS ADS depends on initial diagnosis, and MOG-Ab positivity. Long-term difficulties are observed regardless of relapses and are determined by presenting phenotype.

Assessment of dietary intake and its inflammatory potential in persons with pediatric-onset multiple sclerosis.

OBJECTIVE: To compare diet and the modified dietary inflammatory index (mDII) between individuals with pediatric-onset multiple sclerosis (PoMS), monophasic acquired demyelinating syndromes (monoADS), and controls. METHODS: The association between diet, mDII, and disease status was examined in 131 individuals with PoMS/monoADS/controls (38/45/48) using logistic regression. RESULTS: The associations between diet and PoMS were modest, reaching significance for whole grain intake (adjusted odds ratio, aOR=0.964, 95 % confidence intervals, CI:0.934-0.995) but not mDII (aOR=1.20, 95 %CI:0.995-1.46) versus controls. No findings for monoADS reached significance versus controls. CONCLUSIONS: Individuals with PoMS, but not monoADS, had lower dietary whole grain intake than controls.

Complement-dependent cytotoxicity of human autoantibodies against myelin oligodendrocyte glycoprotein.

Background: The autoantibody to myelin oligodendrocyte glycoprotein (MOG), a component of the central nervous system myelin, has been identified in a subset of demyelinating diseases. However, there is no convincing evidence to support the direct pathogenic contribution of this autoantibody. Objective: To elucidate the role of anti-MOG autoantibodies in human demyelinating disorders, we assessed the effect of autoantibodies on MOG-expressing cells. Methods: Mammalian cells expressing the human MOG protein reacted with human anti-MOG autoantibodies in the presence or absence of complement. Sera from 86 patients and 11 healthy sera were used. We analyzed anti-MOG antibody titers, IgG subclass, and their cytotoxic ability in sera from patients with various neurological diseases. Membrane attack complex (MAC) formation was examined by detection of complement C9 or C9neo with western blot or flow cytometry. Results: Among 86 patients, 40 were determined to be MOG-IgG-positive and 46 were negative. Anti-MOG-positive sera, but not -negative sera, caused cell death in MOG-expressing cells. This cytotoxic effect was disappeared after heat inactivation of sera. Importantly, anti-MOG IgG and externally added complement were necessary for sufficient cytotoxic effects. Anti-MOG autoantibodies were histologically colocalized with complement and formed a membrane attack complex consisting of anti-MOG IgG and complement factors. Conclusion: The human MOG antibody specifically killed MOG-expressing cells in vitro in the presence of externally added complement. Membrane attack complexes were formed on the cells, indicating that this autoantibody activated complement-mediated cytotoxicity. Further studies in larger numbers of patients are needed to characterize the role of complement in MOGAD.

Can early-onset acquired demyelinating syndrome (ADS) hide pediatric Behcet's disease? A case report.

Behcet's disease (BD) is a rare vasculitis characterized by multisystemic inflammation. Central nervous system (CNS) involvement is rare and heterogeneous, particularly in the pediatric population. A diagnosis of neuro-Behcet could be highly challenging, especially if neurological manifestations precede other systemic features; however, its timely definition is crucial to prevent long-term sequelae. In this study, we describe the case of a girl who, at 13 months of age, presented with a first episode of encephalopathy compatible with acute disseminated encephalomyelitis, followed, after 6 months, by a neurological relapse characterized by ophthalmoparesis and gait ataxia, in association with new inflammatory lesions in the brain and spinal cord, suggesting a neuromyelitis optica spectrum disorder. The neurological manifestations were successfully treated with high-dose steroids and intravenous immunoglobulins. In the following months, the patient developed a multisystemic involvement suggestive of Behcet's disease, characterized by polyarthritis and uveitis, associated with HLA-B51 positivity. The challenge presented by this unique case required a multidisciplinary approach involving pediatric neurologists, neuro-radiologists, and pediatric rheumatologists, with all of these specialists creating awareness about early-onset acquired demyelinating syndromes (ADSs). Given the rarity of this presentation, we performed a review of the literature focusing on neurological manifestations in BD and differential diagnosis of patients with early-onset ADS.

Early blood neurofilament light chain and myelin oligodendrocyte glycoprotein antibody levels associate with different disease courses of myelin oligodendrocyte glycoprotein-associated disease in children.

Acquired demyelinating syndrome associated with myelin oligodendrocyte glycoprotein antibodies, named recently myelin oligodendrocyte glycoprotein-associated disease, represents >27% of this paediatric syndrome. Relapses occur in 40% of them, which may be associated with severe outcomes. Aiming to identify biomarker allowing to predict relapse, we measured both myelin oligodendrocyte glycoprotein antibodies and neurofilament light chain levels in blood samples of patients that are known to reflect axonal injuries in neurological diseases including demyelinating autoimmune disorders. Three groups of patients were selected: relapsing myelin oligodendrocyte glycoprotein-associated disease (n = 8), non-relapsing myelin oligodendrocyte glycoprotein-associated disease (n = 7) and control patients with non-inflammatory neurological diseases (n = 12). Neurofilament light chain concentrations were measured in plasma of these three groups of patients using the high-sensitivity single-molecule array method at onset of the disease and 6 months later. At onset of the disease, we found that levels of neurofilament light chain in blood of non-relapsing patients were significantly higher than in control patients (means: 98.36 ± 22.66 versus 12.47 ± 2.47 pg/mL, **P < 0.01, Kruskal-Wallis test). The mean neurofilament light chain value in relapsing patients (82.16 ± 38.41 pg/mL) was not significantly different from that in non-relapsing and in control patients. Plasma myelin oligodendrocyte glycoprotein antibody levels were 2.5-fold higher in relapsing than in non-relapsing patients without reaching significance (means: 15.26 ± 4.87 versus 5.96 ± 1.13; two-tailed Mann-Whitney U-test P = 0.119). Plasma neurofilament light chain correlated significantly with myelin oligodendrocyte glycoprotein antibody levels in relapsing (two-tailed Spearman r = 0.8, P = 0.0218) but not in non-relapsing (two-tailed Spearman r = 0.17, P = 0.71). Interestingly, the ratio of neurofilament light chain-to-myelin oligodendrocyte glycoprotein antibodies was significantly lower in relapsing than in non-relapsing patients (means: 5.19 ± 1.61 versus 21.87 ± 6.13; two-tailed Mann-Whitney U-test P = 0.014). These findings suggest that measuring both neurofilament light chain and myelin oligodendrocyte glycoprotein antibody levels in patients at onset of demyelinating disease could predict relapse of myelin oligodendrocyte glycoprotein-associated disease.

Evaluation of inflammatory acquired demyelinating syndromes in children: a single-center experience.

To evaluate the clinical and neuroimaging features of pediatric acquired demyelinating syndromes (ADS) in a tertiary pediatric neurology clinic in Turkey. All children diagnosed with any subset of ADS between 2013 and 2018 were included in this retrospective cohort study. Forty-two patients (21 female) with a median follow-up period of 30 months were included. The median age of the patients at disease onset was 11 years (range 1.5-17 years). The most common pediatric ADS categories according to the International pediatric Multiple Sclerosis Study Group consensus classification criteria were acute disseminated encephalomyelitis (ADEM) and multiple sclerosis (MS), each of which seen in 15 patients, followed by clinically isolated syndrome (CIS) (n = 11) and Neuromyelitis Optica Spectrum Disorder (NMOSD) (n = 1). At the first clinical event, children with ADEM significantly differed from the children affected by MS and CIS in terms of the following parameters: median age at onset (7 vs. 13.5 and 14.5 years; p < 0.001), encephalopathy (93.3 vs 0% and 0%; p < 0.001), and basal ganglia/thalamus lesions (73.3 vs 9.1% and 9.1%; p < 0.001). The frequency of seizure and pleocytosis were higher in ADEM group than MS group (p < 0.05), whereas oligoclonal bands (p < 0.001) and periventricular white matter lesions (p < 0.01) were more frequently observed in MS patients. Rituximab was used with great success in the prevention of relapses in 3 patients: NMOSD (n = 1), MS (n = 1) and ADEM followed by recurrent optic neuritis (n = 1). Our results define the longitudinal disease course of various ADS categories in a single referral center. In addition, this study compares various clinical, laboratory and neuroimaging features between these ADS categories.

Clinical and Magnetic Resonance Imaging Characteristics of Pediatric Acute Disseminating Encephalomyelitis With and Without Antibodies to Myelin Oligodendrocyte Glycoprotein.

Background: Myelin oligodendrocyte glycoprotein-immunoglobulin G (MOG-IgG)-associated disorders (MOGADs) have been considered as a new inflammatory disease entity of the central nervous system (CNS) and have heterogeneous clinical and imaging presentations. Acute disseminated encephalomyelitis (ADEM) is one of the most important phenotypes. Our research is aimed to compare the clinical and magnetic resonance imaging (MRI) characteristics of ADEM with or without MOG-IgG in pediatric-acquired demyelinating syndromes (ADSs). Methods and Results: We retrospectively reviewed the clinical characteristics, MRI features, and outcomes of pediatric patients with ADSs from March 2017 to February 2021 in our center. MOG-IgG was analyzed by transfected cell-based assay (CBA). Among 46 children with ADEM, 21 children (11 girls and 10 boys) were positive for MOG-IgG. Headache, fever, vomiting, vertigo, ataxia, and decreased muscle strength were common in all enrolled children. No significant difference existed in demographic characteristics, symptoms at an initial episode, or laboratory cerebrospinal fluid (CSF) findings between children with MOG-IgG and children without MOG-IgG. For children with MOG-IgG seropositive ADEM, cerebral MRI showed widespread, poorly demarcated bilateral lesions, especially in cortical and subcortical white matter, and spinal MRI often showed lesions spanning more than three segments. The significant difference in MRI features between the two groups was the presence of lesions in the thalamus and cortical area (p < 0.05). Most children in both groups showed clinical improvement 1 week after immunotherapy and achieved recovery during their hospital stay. Three children with MOG-IgG and four children without MOG-IgG had one or more relapsing courses with median interattack intervals of 4 (range: 1-7) months and 10 (range: 1-24) months, respectively. New clinical symptoms and lesions on cerebral and spinal MRI were found during relapsing courses in two groups. No recurrences were recorded 6-51 months after each patient's last episode. Conclusions: There was no significant difference in clinical characteristics between ADEM children with MOG-IgG and ADEM children without MOG-IgG. For children with MOG-IgG seropositive ADEM, cerebral MRI showed large, bilateral lesions and spinal MRI often showed lesions spanning more than three segments. Children achieved a favorable outcome regardless of MOG-IgG serostatus.

Acute Demyelinating Syndromes: A report of child neurology department of Sfax University Hospital.

INTRODUCTION: The yearly incidence of Acute Demyelinating Syndromes (ADS) in a multiethnic cohort of children published by Langer-Gould and al in 2011 was estimated at about 1.66 per 100,000. Nevertheless, the real incidence for these disorders is still underestimated as the iterative revision for diagnosis criteria have failed to classify a significant number of children with ADS. PURPOSE: This work was aimed to describe clinical and paraclinical characteristics of ADS in a pediatric population. MATERIAL AND METHODS: Demographic, clinical and paraclinical data of 42 children (24 females; 18 male; SR = 1.33), were collected from the medical records of patients admitted to the child neurology department of Sfax University Hospital between 2008 and 2021 for clinical events with presumed inflammatory origin. Next, patients were categorized as per M. N. Nouri and al. up dated classification for ADS. Finally, characteristics of different ADS categories were compared. RESULTS: The mean age onset was 6 years (± 3.5 years). For a mean follow-up period of 28 months, 69% of patients had a monophasic course. ADS in our pediatric population were Acute disseminated encephalomyelitis (ADEM) (36%), Clinically isolated syndrome (CIS) (24%), Multiple sclerosis (MS) (19%), Neuromyelitis optica spectrum disorder (NMOSD) (7%), Myelin oligodendrocyte glycoprotein antibodies-associated diseases (MOGAD) (2%) and Recurrent demyelinating disease not otherwise specified (RD-NOS) (10%). At presentation, patients showed different clinical picture according to ADS-subtype with more patients with epileptic seizure in ADEM-group (53.3%), optic neuritis in CIS-group (70%), motor deficit in MS-group (62.5%), area postrema syndrome in NMOSD-group (33.3%) and vesico-sphincter dysfunction in RD-NOS-group (75%). Among patients presenting with visual impairment (21.4%), Visual evoked potential (VEP) guided the diagnosis of NMOSD in 22.2% by objectifying axonal optic nerve damage. Different ADS subtypes were identified according to MRI results in 100% of ADEM-patients and 75% of MS-patients and on antibody testing in three patients. The ADS-subtype was recognized based on antibody testing in three patients. Two patients from CIS-group: the first with isolated optic neuritis (ON) was positive for antiaquaporin 4 antibodies (anti-AQP4) and the other with clinically polyfocal ADS was positive for antinuclear antibodies (ANA) type anti-RNP. The remaining patients who presented with ADEM-phenotype was positive for anti-myelin oligodendrocyte glycoprotein (anti-MOG). SIGNIFICANCE: Recognizing distinctive features of each ADS category may improve diagnosis accuracy as well as the indication of suitable treatment.

Pediatric Optic Neuritis: Description of Four Cases and Review of the Literature.

Pediatric optic neuritis (PON) may be a clinically isolated and self-limiting event or may present in the context of underlying neurologic, infective, or systemic disease. PON has a high impact on the quality of life as it may or may not evolve into other acquired demyelinating syndromes (ADSs), such as multiple sclerosis (MS), neuromyelitis optica (NMO), or other syndromes related to the myelin oligodendrocyte glycoprotein IgG antibodies (MOG-IgG). These different PON phenotypes present variable clinical and radiological features, plasma and liquor biomarkers, and prognosis. We describe four pediatric cases presenting clinically with ON, with different etiopathogenetic pictures: one case had a probable infective etiology, while the others were associated with different demyelinating disorders (MS, NMO, syndrome related to MOG-IgG). We discuss the possible evolution of presenting ON in other ADSs, based on recent literature. A careful evaluation of the clinical and investigation findings and the natural course of PON is necessary to define its pathogenic pathway and evolution. Further prolonged follow-up studies are needed to highlight the predictors of PON evolution, its potential sequelae, and the best treatment options.

Clinical and Prognostic Analysis of Autoantibody-Associated CNS Demyelinating Disorders in Children in Southwest China.

Objective: To analyze the positive and recurrence rates of different autoantibody-associated demyelination disorders in children in Southwest China, and describe the clinical, radiological, and prognostic features of the myelin oligodendrocyte glycoprotein antibody (MOG-ab) and aquaporin-4 antibody (AQP4-ab) associated disease. This study also summarizes steroid maintenance therapy approaches for MOG-ab-positive children. Methods: A total of 160 children presenting with acquired demyelinating syndromes (ADS) between January 2016 and December 2019 were tested for MOG-ab and AQP4-ab. Clinical data, MRI scans, and survival analyses were compared between MOG-ab-positive and AQP4-ab-positive children. Evolution of serologic status and treatment response to immunosuppressants were collected in MOG-ab-positive children. Results: Of the 160 included children, the MOG-ab positivity rate (47.4%) was significantly higher than the AQP4-ab (5%) positivity rate. The recurrence rate for AQP4-ab disease (71.4%) was higher than that of MOG-ab disease (30.1%). For 135 children with both MOG-ab and AQP4-ab tested, the median age at onset was 7 (interquartile range [IQR] 5-10) years, and the median follow-up period was 19 (IQR 13-27.5) months. MOG-ab-positive children more frequently presented with acute disseminated encephalomyelitis, had deep gray matter lesions on MRI, had a better clinical and radiological recovery, and were less likely to have sustained disability than AQP4-ab-positive children. In MOG-ab-positive and AQP4-ab-positive children, maintenance therapy was a protective factor for recurrence, but presenting optic neuritis was a predictor of earlier relapse. A high Expanded Disability Status Scale score at onset was associated with sustained disability. Steroid maintenance therapy longer than 6 months after the initial attack was associated with a lower risk of a second relapse in MOG-ab-positive children. On serial serum MOG antibody analysis, clinical relapse occurred in 34.6% of children with persistent seropositivity, but none of the children who converted to seronegative status experienced relapse. Conclusion: The MOG antibody is more common in children with ADS than the AQP4 antibody. MOG-ab-positive children are characterized by distinct clinical and radiological features. Although some MOG-ab-positive children experience relapsing courses or have persistently seropositive status, they still predict a better outcome than AQP4-ab-positive children.

Clinical and neuroimaging characteristics of MOG autoimmunity in children with acquired demyelinating syndromes.

Background Myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) have been recently reevaluated as a biomarker of acquired demyelinating syndromes (ADS) of the central nervous system (CNS). Here, we describe the clinical and neuroimaging features, and the long-term outcome of children with ADS of the CNS associated with MOG-IgG. Methods All patients underwent brain and spinal cord magnetic resonance imaging (MRI), lumbar puncture for cerebrospinal fluid (CSF) analysis and MOG-IgG and aquaporin-4 IgG (AQP4-IgG) testing. Results Forty-eight pediatric patients were recruited. MOG-IgG were detected in 11/48 (25%) patients with the following clinical presentations: encephalomyelitis (EM), 8/11 (73%); optic neuritis (ON), 2/11 (18%); transverse myelitis (TM), 1/11 (9%). Patients negative for MOG-IgG were diagnosed with Multiple Sclerosis (MS) (n=15), EM (n=7), ON (n=7), neuromyelitis optica spectrum disorders (NMOSD) (n=5), TM (n=2) and encephalitis (n=1). MOG-IgG positive patients were younger at disease onset and they more frequently experienced encephalopathy and epileptic seizures compared with negative patients. EM and inflammatory lesions involving optic nerves on MRI imaging were more frequent in MOG-IgG positive patients. None of the patients with MOG-IgG became persistently seronegative during the follow-up, although a decrease in MOG-IgG titer was observed. Patients with MOG-IgG showed a good response to therapy and only two patients presented relapses during follow-up. Conclusion This study supports the distinction of MOG autoimmune oligodendrocytopathy as a unique disease entity, with clinical features different from those of MS and AQP4-IgG-positive NMOSD.