Objective:To evaluate the efficacy and safety of rituximab in pediatric myasthenia gravis (MG).Methods:Case series study. The clinical manifestations, laboratory tests, treatment plans and prognosis of 27 pediatric MG patients treated with rituximab from June 2013 to June 2023 at Children′s Medical Center of Peking University First Hospital were retrospectively collected.Results:There were 5 males and 22 females in 27 MG children. The onset age was 2.1 (1.6, 4.8) years, ranging from 8 months to 11 years. The clinical classification included 20 children (74%) of ocular MG and 7 children (26%) of generalized MG. Seventeen children (63%) had positive MG-related pathogenic antibodies, including 17 children of anti-AchR antibody and 1 of them also had anti-MuSK antibody. Rituximab was used as first-line immunosuppressant in 13 children, second-line immunosuppressant in 13 children and third-line immunosuppressant in 1 child. Immunosuppressants used before rituximab including 8 children of cyclosporine, 3 children of tacrolimus, 1 child of azathioprine, 1 child of mycophenolate mofetil and 1 child of cyclosporine combined with azathioprine. Rituximab was used for at least half a year with a follow-up period of more than 12 months. At the last follow-up after rituximab treatment, all children achieved improved or above, 14 children (52%) achieved complete stable remission, 7 children (26%) achieved pharmacologic remission, 1 child (4%) achieved minimal manifestations, and 5 children (18%) improved. After rituximab treatment, 27 children all could reduce the immunomodulation therapy and shorten the course of glucocorticoid therapy, and 22 children (81%) had stopped the glucocorticoid therapy. Among the 14 children with poor efficacy of other immunosuppressants, rituximab had complete stable remission of 7 children. The most common adverse reaction was respiratory infection (4 children (15%)). Only 2 children had allergic reaction to rituximab and got better after symptomatic treatment.Conclusions:Rituximab has good efficacy and tolerance in pediatric MG. Early application of rituximab can improve the prognosis and shorten the course of glucocorticoid treatment.

Objective:To summarize the clinical characteristics of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) and compare the differences in efficacy of different disease-modifying drugs.Methods:An ambispective cohort study was conducted in 42 children diagnosed with MOGAD at Department of Pediatrics, Peking University First Hospital from January 2012 to March 2021 and conducted long-term follow-up to analyze clinical phenotypes and compare the efficacy of different disease-modifying drugs such as rituximab, mycophenolate mofetil and azathioprine. Kruskal-Wallis H test was used to compare the annual relapse rate of disease-modifying drugs at different times, expanded disability status scale (EDSS) score at the last follow-up, and Wilcoxon rank test was used to compare the annual relapse rate before and after modified disease therapy. The Log-rank (Mantel-Cox) survival curve was used to compare the relapse rate of different disease-modifying drugs. Results:Of the 42 cases, 22 were male and 20 were female, with the age at disease onset of 5.96 (2.33-12.90) years. The disease duration was 4.46 (1.25-13.00) years at the last follow-up with 161 clinical acute attacks. Acute disseminated encephalomyelitis (ADEM) was the most common phenotype of first attack and all attacks during disease course ((60% (25/42) for first attack, 38% (61/161) for all attacks). The most common clinical syndrome was neuromyelitis optica spectrum disorders (NMOSD) (50%, 21/42). Of the 42 children, 5 (12%) showed encephalitis and 6 (14%) combined with anti-N-methyl-D-aspartate receptor (NMDAR) antibody overlap syndrome. The most commonly involved areas of brain magnetic resonance imaging (MRI) were subcortical white matter (71%, 88/124), cortex (26%, 32/124) and periventricular white matter (25%, 32/124). Spinal cord MRI was most frequently involved in cervical (70%, 16/23) and thoracic (61%, 14/23) medulla, and 43% (10/23) longitudinally extensive transeverse myelitis. Disease-modifying drugs were used in 34 patients. The annual relapse rate after treatment with rituximab, mycophenolate mofetil and azathioprine decreased (all P<0.05) and there was no statistically significant difference in the annual relapse proportion among the groups ( P=0.307). Conclusions:The most common clinical attack of first and all of MOGAD in children is ADEM, and the most common clinical syndrome is NMOSD. Rituximab, mycophenolate mofetil and azathioprine can reduce the annual relapse rate, but it is not clear effect of which treatment is better.

Objective:To investigate the normal range of exhaled nitric oxide (FeNO) in 6-18-year-old children in China, so as to provide a data base for the establishment of FeNO standards for Chinese children.Methods:A multi-center study was conducted on 5 949 children aged 6-18 (3 101 males and 2 848 females) in 16 pro-vinces of 7 administrative districts in China.According to the technical standard recommended by American Thoracic Society/European Respiratory Association, FeNO was measured, and the relationship of FeNO with the sex, age, height, weight, body mass index and region was discussed.Results:The geometric mean FeNO value of Chinese children aged 6-18 was 14.1 ppb, and its 95% confidence interval (skewness distribution) was 1.0-38.2 ppb.The geometric mean FeNO values of children aged 6-11 and 12-18 were 13.1 ppb and 15.7 ppb, respectively, and their 95% confidence intervals (skewness distribution) were 1.0-38.1 ppb and 2.0-38.2 ppb.For children at and under 11 years old, FeNO decreased with age, with a mean decline of 1 ppb per year.The multiple linear regression results suggested that there was a significant correlation between FeNO and age for children aged 6-11, and FeNO of children aged 12-18 was significantly correlated with the gender, height, and region(all P<0.01). Conclusions:FeNO values of Chinese children and adolescents in this study are higher than those obtained by the previous study conducted from 2010 to 2012.For children aged 12-18, 16 ppb is recommended as the clinical cut-off point.For children at or under 11 years old, the influence of age on FeNO should be considered, and the cut-off point of FeNO decreases by 1 ppb as the age is reduced by one year.

Objective: To explore clinical features and the effect of treatment of neuromyelitis optica spectrum disorders (NMOSD) in childhood. Methods: Children who were hospitalized in Department of Pediatrics, Peking University First Hospital from January 2013 to June 2018 and meeting diagnostic criteria of NMOSD proposed by the International Panel for NMOSD Diagnosis in 2015 were summarized and followed up. The basic information, symptoms of each attack, locations and patterns of new lesions, features of cerebrospinal fluid, serologic markers, treatments and outcomes in these patients were analyzed. Thirty-three children were included in the study, with 13 males and 20 females. The median age of onset was 6.83 (4.25, 8.75) years. Compared aquaporin-4 immunoglobulin G (AQP4-IgG) associated NMOSD with myelin oligodendrocyte glycoprotein immunoglobulin G (MOG-IgG) associated NMOSD. Mann-Whitney U test was used for continuous variables and Fisher test for categorical variables in comparison between AQP4-IgG and MOG-IgG associated NMOSD. Wilcoxon test was used for annualized relapse rate (ARR) before and after adding disease-modifying drugs. Results: Optic neuritis (39% (13/33) in initial attacks and 49% (62/127) in total attacks) and myelitis (36% (12/33) in initial attacks and 26% (33/127) in total attacks) were the top two symptoms in both the initial attacks and all 127 attacks during follow-up. There was 42% (37/89) of brain magnetic resonance imaging (MRI) scans in acute phase showing new lesions in supratentorial white matter, with 43% (16/37) showing acute disseminated encepha lomyelitis (ADEM)-like or leukodystrophy-like patterns. AQP4-IgG was detected in 30% (10/33) patients, and MOG-IgG was detected in 55% (11/20) patients, with no combined positive case. In 20 patients treated with rituximab, two were treated after the initial attack. In the other 18 patients, the median annualized relapse rate decreased from 1.86 (1.52, 2.60) before treatment to 0.28 (0, 1.13) during treatment (Z=-3.376, P=0.001). Compared with AQP4-IgG associated NMOSD (10 cases), fever of unknown origin (8/40 vs. 0/33, P=0.007) was more common, area postrema syndrome (0/40 vs. 4/33, P=0.038) was fewer, cell count of cerebrospinal fluid (49.0 (17.5, 115.0) ×10⁶/L vs. 5.5 (3.0, 15.8)×10⁶/L, Z=-3.526, P=0.000) was higher in MOG-IgG associated NMOSD (11 cases). Conclusions In childhood-onset NMOSD, optic neuritis and myelitis were top two symptoms. Childhood-onset NMOSD has high proportion of positive MOG-IgG. Lesions in supratentorial white matter are common. Rituximab could significantly decrease ARR of NMOSD in childhood. However, more studies should be conducted to explore the optimal treatment strategy in different antibody associated NMOSD.

Objective: To summarize the clinical and genetic features of β-propeller protein-associated neurodegeneration (BPAN). Methods: The clinical data of 17 patients with BPAN with WDR45 gene variants were retrospectively collected at Children’s Hospital of Fudan University, Peking University First Hospital, Capital Institute of Pediatrics, Shengjing Hospital of China Medical University and Shanghai Children's Hospital from June 2016 to December 2018, and their clinical manifestations, electroencephalogram, neuroimaging and genetics were analyzed. Results: Seventeen cases (13 females, 4 males), aged 1.1-8.8 years, were included. The median age of seizure onset was 14.5 months, from 3 months to 24 months of age, manifested with epileptic spasm in 6 cases and focal seizures in 5 cases. Eight patients had only one seizure type and 8 patients had two or more seizure types. Nine patients had complete remission of seizures. All 16 patients with seizures had developmental delay before the seizure onset, of whom 13 patients had moderate to severe seizures. The brain magnetic resonance imaging (MRI) was abnormal in 13 patients, including cerebral atrophy (10 cases) and thinning of the corpus callosum (9 cases). The brain magnetic susceptibility weighted imaging (SWI) in preschool stage showed prominent T2 hypointense signals in bilateral globus pallidus and brainstem ventral in two cases. Five seizure types (spasm, focal, absence, myodonic and generalized tonic clonic seizures)were found on ictal electroencephalogram(EEG) recordings. Compared to female patients(17(6-24) months of ege), male cases had earlier seizure onset (3, 4, 5, 18 months of age) . All patients had de novo variations in WDR45(6 nonsense, 4 frameshift, 3 missense and 4 splicing variations), with hemizygous variants in 3 males, mosaic variants in a male and heterozygous variants in 13 females, within which 5 variations had not been reported (c.977-1C>T,c.976+1G>C,c.10C>T,c.806del and c.110T>C). Conclusions The patients with BPAN have profound developmental delay and are vulnerable to seizures. The male patients with BPAN tend to have more severer clinical phenotype than females. Early brain SWI could facilitate the timely diagnosis of this disease.

Objective To identify the pathogenic gene variants and clinical phenotype features of 26 children with progressive myoclonic epilepsy (PME).Methods In this cross-sectional study,26 PME children (11 boys and 15 girls) sent to neurological outpatient clinics and admitted to wards of the Department of Pediatrics,Peking University First Hospital were enrolled prospectively from January 2014 to October 2018.The pathogenic gene variants of PME children and their parents were identified by Sanger sequencing,next generation sequencing panels of epilepsy or trio-based whole exome sequencing and so on.The genotypes and phenotypes of the PME children were anaylzed.Results The clinical features of 26 children include myoclonus,multiple types of seizures and progressive neurological regression.Their onset ages ranged from 3 months to 15 years.Several pathogenic gene variants were identified in the 15 patients,including TPP1 gene variantions in 3 patients;NEU1,GBA,TBC1D24 and KCNC1 gene variantions in 2 patients respectively;CLN6,MFSD8,ASAH1 and ATN1 gene variantions in 1 patient respectively.Several variants of uncertain significance were identified in 4 patients,including GOSR2 gene compound heterozygous variants in 2 patients,KCTD7 gene compound heterozygous variants in 1 patient,and compound heterozygous variants of an unreported TARS gene in 1 patient.No pathogenic gene variant was identified in 7 patients.In 15 children with the identified pathogenic gene variants,5 patients were diagnosed with neuronal ceroid lipofuscinoses (NCL),2 patients with sialidosis,2 patients with neuronopathic Gaucher disease,1 patient with dentatorubral-pallidoluysian atrophy (DRPLA),and 1 patient with spinal muscular atrophy-progressive myoclonic epilepsy (SMA-PME).Conclusions PME include a group of diseases with genetic heterogeneity.Identification of the pathogenic gene variants of PME could help to predict the prognosis and guide the genetic counseling.

To summarize the clinical and genetic features of β?propeller protein?associated neurodegeneration (BPAN). Methods The clinical data of 17 patients with BPAN with WDR45 gene variants were retrospectively collected at Children's Hospital of Fudan University, Peking University First Hospital, Capital Institute of Pediatrics, Shengjing Hospital of China Medical University and Shanghai Children's Hospital from June 2016 to December 2018, and their clinical manifestations, electroencephalogram, neuroimaging and genetics were analyzed. Results Seventeen cases (13 females, 4 males), aged 1.1-8.8 years, were included. The median age of seizure onset was 14.5 months, from 3 months to 24 months of age, manifested with epileptic spasm in 6 cases and focal seizures in 5 cases. Eight patients had only one seizure type and 8 patients had two or more seizure types. Nine patients had complete remission of seizures. All 16 patients with seizures had developmental delay before the seizure onset, of whom 13 patients had moderate to severe seizures. The brain magnetic resonance imaging (MRI) was abnormal in 13 patients, including cerebral atrophy (10 cases) and thinning of the corpus callosum (9 cases). The brain magnetic susceptibility weighted imaging (SWI) in preschool stage showed prominent T2 hypointense signals in bilateral globus pallidus and brainstem ventral in two cases. Five seizure types (spasm, focal, absence, myodonic and generalized tonic clonic seizures) were found on ictal electroencephalogram(EEG)recordings. Compared to female patients(17(6-24) months of ege), male cases had earlier seizure onset (3, 4, 5, 18 months of age). All patients had de novo variations in WDR45 (6 nonsense, 4 frameshift, 3 missense and 4 splicing variations), with hemizygous variants in 3 males, mosaic variants in a male and heterozygous variants in 13 females, within which 5 variations had not been reported (c.977?1C>T,c.976+1G>C,c.10C>T,c.806del and c.110T>C). Conclusions The patients with BPAN have profound developmental delay and are vulnerable to seizures. The male patients with BPAN tend to have more severer clinical phenotype than females. Early brain SWI could facilitate the timely diagnosis of this disease.

Objective To summarize the clinical and prognostic features of anti - N - methyl - D - aspartate receptor (NMDAR)encephalitis with demyelinated lesions and discuss the possible pathogenesis. Methods The clini-cal and imaging features of 3 pediatric patients diagnosed as anti - NMDAR encephalitis with demyelinated lesions were analyzed. The published papers were browsed by using " anti - NMDA receptor encephalitis" and " demyelinating"as key words into CNKI,Wanfang and PubMed database from starting point to May,2017. Results In 3 cases,anti -NMDAR encephalitis occurred simultaneously with demyelinated episodes in 2 cases,successively in the other case. One case had AQP4 - IgG positive. Two cases had recurrent course,and 1 case had a single course and poor prognosis. A to-tal of 15 articles reported 41 cases,including 16 (39. 02％)pediatric cases. In these pediatric cases,anti - NMDAR encephalitis occurred in 7 cases (43. 75％)successively and demyelinated episodes occurred in 9 cases (56. 25％) simultaneously. AQP4 antibody and MOG antibody in serum and/ or cerebrospinal fluid were detected in all cases,with either of two antibodies positive in 9 cases (56. 25％). Conclusion Anti - NMDAR encephalitis might occur simulta-neously or successively with demyelinated episodes. Compared with typical patients with anti - NMDAR encephalitis, patients with demyelinated lesions are more likely to relapse and have worse outcomes. Anti - NMDAR encephalitis and demyelinated lesions are both based on similar immune dysfunction or demyelinated lesions are also induced by anti -NMDAR antibodies,which is the probable pathogenesis.

Objective To explore the clinical features and pathogenic genes of sialidosis. Methods The clinical data and genetic test results of a family with sialidosis were retrospectively analysed. Results The proband was a 13-year-old girl who presented with limb pain at age 7, followed by progressive vision loss and convulsive seizure. In addition, she also had the sign of ataxia. Fundus examination showed optic atrophy in her eyes. Visual evoked potential showed that the latency of binocular P100 was significantly prolonged. The elder brother of the proband showed similar manifestation. PCR was used to amplify the exons and exon-intron boundaries of the NEU1 gene, and DNA direct sequencing was used to detect the mutation in this gene. It was found that both proband and her brother carried two known pathogenic heterozygous mutations in the NEU1 gene, c.239C>T (p.P80L) and c.544A>G (p.P80L) respectively from both their mother and father of normal phenotype. Conclusion The causative mutation of the NEU1 gene in the family of sialidosis has been defined.

Objective: To assess the effectiveness and safety of rituximab in Chinese children with autoimmune diseases of the nervous system. Method: An ambispective cohort study enrolled patients with refractory and(or) relapse autoimmune diseases of nervous system from June 2010 to June 2016 in Peking University First Hospital.These patients failed to respond to steroids and(or)intravenous immunoglobulin (IVIG) were treated with rituximab and seen for follow-up visits once every 3 months.The effectiveness was assessed by modified Rankin scale (mRs) and the annualized relapse rate.B cell was repeatedly counted after the treatment.Side effects attributed to rituximab were recorded.Paired rank test and chi-square test were used to compare the mRs score and the recurrence rate (time/year) before and after the treatment. Result: A total of 38 patients (15 males and 23 females) with mean age of (6±4) years were treated with rituximab.Among those patients, 4 cases were in multiple sclerosis, 5 in neuromyelitis optica, 6 in opsoclonus myoclonus syndrome, 9 in myasthenia gravis, and 14 in autoimmune encephalitis and other nervous system autoimmune diseases.The course of the disease before rituximab treatment was from two months to 7.25 years, with the average of (21±19) months.The patients had been followed up for 2-52 months. The mRs score and recurrence rate of 38 patients before receiving rituximab was 3 points (3, 4) and 2.56 (1.80, 4.75) times per year, respectively, while patients after receiving rituximab were mRs score of 0 (0, 2) and had a recurrence rate of 0 (0, 0.17) per year.There was statistical difference before and after treatment (Z=-4.51 and -4.71, P<0.01). Rituximab had a definite benefit in 23 patients, probable benefit in 2 patients, possible benefit in 3 patients, no benefit in one patient, and the disease worsened in 2 patients.Therefore the total effective rate was 74%, except for 6 undetermined cases because of the short follow-up time, and one patient withdrew from the study due to allergic reaction.During the follow-up, only one patient with severe allergy gave up the rituximab treatment. And only one patient was found severe infection with Pneumocystis carinii pneumonia. Conclusion Rituximab is an effective and safe treatment strategy for patients with refractory and relapse autoimmune diseases of CNS, especially in neuromyelitis optica and myasthenia gravis.The adverse events including infection and allergy during infusion are not common.