Clinical Presentation, Management, and Diagnostic Performance of 2021 Criteria for Paraneoplastic Neurologic Syndromes in Childhood.

BACKGROUND AND OBJECTIVES: Paraneoplastic neurologic syndromes (PNSs) are remote neurologic immune-related effects of tumors. The clinical characteristics of pediatric PNSs remain unclear. We retrospectively examined the clinical characteristics of cases of pediatric PNSs and assessed the performance of the 2021 diagnostic criteria in children. METHODS: Patients hospitalized in the Beijing Children's Hospital between June 2015 and June 2023 and fulfilling the description of definite by 2004 diagnostic criteria of PNSs were included. A retrospective analysis of clinical characteristics was conducted, and the 2021 diagnostic criteria were applied to rediagnostic stratification. RESULTS: Among the 42 patients included, the most common neurologic syndrome was opsoclonus-myoclonus syndrome (OMS) (62%), followed by rapidly progressive cerebellar syndrome (26%). Most tumors were neuroblastomas (88%), with few being ovarian teratomas (10%). Approximately 71% (30/42) of patients were classified as definite and 24% (10/42) as probable according to the 2021 criteria. All cases judged as probable exhibited rapidly progressive cerebellar ataxia with neuroblastoma. For OMS, chemotherapy was administered based on the tumor's risk stage, accompanied by regular infusion of IV gamma globulin and oral steroids following tumor diagnosis. Twenty-one patients underwent regular follow-ups over 4.92 (0.58-7.58) years. The initial hospitalization recorded a median score of 12 (7-14) on the Mitchell and Pike OMS rating scale, decreasing to 0 (0-5) at the final follow-up. In cases of rapidly progressive cerebellar syndrome, a similar therapeutic regimen was used. Nine patients underwent regular follow-ups over 4.42 (1.17-7.50) years. The mean modified Rankin scale score at first hospitalization was 4 (3-4), reducing to 1 (0-4) at the final follow-up. Only 17% (5/30) of patients across both groups exhibited poor response to this regimen. Among these 5 patients, 4 belonged to the low-risk group (without chemotherapy). DISCUSSION: OMS followed by rapidly progressive cerebellar ataxia are the most common forms of PNSs in children and are associated with neuroblastoma. An aggressive approach with multiple immunotherapies may improve the prognosis of neuroblastoma-associated PNSs. The 2021 criteria perform well in pediatric PNSs. However, we propose upgrading the classification of antibody-negative rapidly progressive cerebellar ataxia with neuroblastoma to definite diagnosis. This adjustment aims to further improve the diagnostic efficacy of this diagnostic criterion in childhood.

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.

De novo frameshift variant in MT-ND1 causes a mitochondrial complex I deficiency associated with MELAS syndrome.

BACKGROUND: The variant m.3571_3572insC/MT-ND1 thus far only reported in oncocytic tumors of different tissues. However, the role of m.3571_3572insC in inherited mitochondrial diseases has yet to be elucidated. METHODS: A patient diagnosed with MELAS syndrome was recruited, and detailed medical records were collected and reviewed. The muscle was biopsied for mitochondrial respiratory chain enzyme activity. Series of fibroblast clones bearing different m.3571_3572insC variant loads were generated from patient-derived fibroblasts and subjected to functional assays. RESULTS: Complex I deficiency was confirmed in the patient's muscle via mitochondrial respiratory chain enzyme activity assay. The m.3571_3572insC was filtered for the candidate variant of the patient according to the guidelines for mitochondrial mRNA variants interpretation. Three cell clones with different m.3571_3572insC variant loads were generated to evaluate mitochondrial function. Blue native PAGE analysis revealed that m.3571_3572insC caused a deficiency in the mitochondrial complex I. Oxygen consumption rate, ATP production, and lactate assays found an impairment of cellular bioenergetic capacity due to m.3571_3572insC. Mitochondrial membrane potential was decreased, and mitochondrial reactive oxygen species production was increased with the variant of m.3571_3572insC. According to the competitive cell growth assay, the mutant cells had impaired cell growth capacity compared to wild type. CONCLUSIONS: A novel variant m.3571_3572insC was identified in a patient diagnosed with MELAS syndrome, and the variant impaired mitochondrial respiration by decreasing the activity of complex I. In conclusion, the genetic spectrum of mitochondrial diseases was expanded by including m.3571_3572insC/MT-ND1.

Cerebral small vessel disease caused by PLOD3 mutation: Expanding the phenotypic spectrum of lysyl hydroxylase-3 deficiency.

Introduction: Pathogenic variants in PLOD3, encoding lysyl hydroxylase-3 (LH3), can cause a hereditary connective tissue disorder that has rarely been reported. It is a multi-system disease, presenting with craniofacial dysmorphisms, skeletal and eye manifestations, sensorineural hearing loss, and variable skin manifestations. Severe central nervous system involvement has not been reported. Case presentation: A 10-month-old girl was admitted with development delay and clustered epileptic spasms. Hypertelorism, an upturned nose, and low-set ears were noted in physical examination. Cerebral magnetic resonance imaging showed multiple intracranial malacias and bleeding foci, extensive abnormal signals in the white matter, and obvious brain atrophy, which was consistent with cerebral small vessel disease (SVD). Electroencephalography suggested hypsarrhythmia. The vertebrae were flattened. The distal end of the metacarpal bone in the left hand was irregular. She was diagnosed with West syndrome. Whole-exome sequencing revealed a novel homozygous variant of c.1216_1218delCTC (p.L406del) in PLOD3, which was found to be inherited from her heterozygous parents. Conclusion: We report a patient with pathogenic PLOD3 mutation who presented with cerebral SVD. This report expands the phenotypic spectrum of LH3 deficiency.

Mycophenolate mofetil: An alternative disease-modifying agent for MOG-IgG-associated disorders in childhood: A single-center bidirectional cohort study.

OBJECTIVE: To evaluate the efficacy of mycophenolate mofetil (MMF) in the treatment of childhood MOG-IgG-associated disorder (MOGAD). METHODS: Thirty patients diagnosed with relapsing MOGAD and treated with MMF for >1 year from a childhood MOGAD ambispective cohort were included in the study. The clinical characteristics, therapeutic regimen, side effects, annualized relapse rate (ARR), and Expanded Disability Status Scale (EDSS) scores of these patients were evaluated. RESULTS: The median age of disease onset was 7.05 (2.50-12.75) years. The male to female ratio was 1:1.31. All patients used MMF as first-line maintenance treatment. The median time to add MMF from disease onset was 1.08 (0.25-5.00) year. The median number of attacks before MMF initiation was 2 (2 - 8). The median duration of MMF therapy was 2.13 (1.00-3.58) years. Twenty (66.67%) patients did not experience further attacks during MMF therapy. The Kaplan-Meier curves showed a 3-year relapse-free rate of 59.8% (95% CI, 36.62-76.88%). ARR decreased during MMF therapy (0 (0 - 1.72) vs. 1.25 (0.60-4.00); P < 0.05). EDSS stabilized during MMF therapy (1.0 (0 - 2.0) vs. 0 (0 - 2.0); P = 0.206). None of the patients stopped the use of MMF due to intolerable side effects. Onset age, sex, phenotype of the first attack, ARR before MMF, MOG-IgG titers, and combined long-term prednisone (prednisone <10 mg daily for patients >40 kg or <5 mg daily for patients ≤40 kg longer than 6 months) did not predict recurrence during MMF therapy in univariate analysis. CONCLUSIONS: MMF was effective and safe for treating childhood MOGAD. No clinical feature that could predict efficacy of MMF was found in pediatric patients with MOGAD.

A 5-year-old child presenting with tumor-like primary angiitis of the central nervous system.

Introduction: Primary angiitis of the central nervous system (PACNS) is a vasculitis confined to the CNS. A small proportion of the lesions may present as a tumor-like mass, which is rarely seen in children. Case presentation: A 5-year-old girl was admitted to our hospital because of an intermittent headache. Brain imaging suggested a space-occupying lesion in the right cerebral hemisphere. The final diagnosis was PACNS with a lymphocytic pattern by stereotactic brain biopsy. Her condition improved after immunotherapy. Conclusion: Pediatricians should consider the possibility of PACNS when encountering intracranial tumor-like lesions. Early diagnosis of tumor-like PACNS and prompt immunotherapy could improve the long-term prognosis and avoid surgery.

Chinese patients with p.Arg756 mutations of ATP1A3: Clinical manifestations, treatment, and follow-up.

Importance: The phenotypes of ATP1A3 gene mutations are diverse. Relapsing encephalopathy with cerebellar ataxia and fever-induced paroxysmal weakness and encephalopathy (FIPWE) are considered non-classical phenotypes caused by p.Arg756 mutations of ATP1A3. Objective: To summarize the clinical manifestations, treatment, and follow-up of Chinese patients with p.Arg756 mutations of ATP1A3. Methods: We analyzed the clinical features, treatment, and genotypes of eight children with p.Arg756 mutations of ATP1A3 who were treated in Beijing Children's Hospital from January 2014 to December 2019. Results: Eight patients (six boys and two girls) were included; seven had been misdiagnosed with encephalitis. The age of onset ranged from 0.8 to 4.5 years. All patients had encephalopathy and had at least one episode of FIPWE. Cerebellar ataxia was present in nine episodes. Reversible splenial lesions of the corpus callosum were found in two patients in the acute phase. Three types of heterozygous ATP1A3 mutations were found: c.2267G > T (p.R756L) (patient 3 [P3]), c.2266C > T (p.R756C) (P2 and P4), and c.2267G > A (p.R756H) (P1, P5, P6, P7, and P8). Six mutations were de novo; two mutations were inherited. Both patients with p.R756C and one patient (P7) with p.R756H had four episodes of severe ataxia as the main manifestations. However, in the other three episodes, limb weakness was more prominent than ataxia. P5 with p.R756H exhibited overlap with FIPWE and rapid-onset dystonia-parkinsonism. Interpretation: Acute encephalopathy followed by febrile disease was characteristic of the disease in patients with p.Arg756 mutations of ATP1A3. However, the weakness and ataxia were variable. Phenotypic crossover and overlap were observed among these patients.

Case Report: A Variant Non-ketotic Hyperglycinemia With GLRX5 Mutations: Manifestation of Deficiency of Activities of the Respiratory Chain Enzymes.

Objective: Variant non-ketotic hyperglycinaemia (NKH) is a rare disorder characterized by variable clinical, biochemical, and imaging features. The variant form of NKH is rare and characterized by variable clinical, biochemical and imaging features. Subjects: Herein, we report a girl with variant NKH with two mutations in glutaredoxin 5 (GLRX5), which has been described in only three patients. Results: The clinical and biochemical phenotypes of the patient are also described. She suffered from developmental regression associated with spasticity, developmental delay, anemia and optic atrophy. The mitochondrial leukoencephalopathy was used to designate these disorders. An increased T2 signal from the medulla oblongata to the C6 spinal region was also observed on spinal cord MRI. Tandem mass analysis of a dried blood sample revealed elevated levels of glycine. The patient has two compound heterozygous mutations (c.151_153 del AAG and c.196C>T) in the GLRX5 gene. The c.196C>T mutation led to a stop codon (p.Q66Ter). Activities of mitochondrial respiratory chain (MRC) complexes II+III in the patient's fibroblasts were abnormal. Conclusions: We present the case of a girl with variant NKH who manifested spasticity and bilateral cavitating leukoencephalopathy. The patient had a deficiency of a respiratory chain enzyme, and this is the first report. Genetic testing is important for physicians to evaluate suspected variant NKH patients and to provide proper genetic counseling.

Neurologic Manifestations as Initial Clinical Presentation of Familial Hemophagocytic Lymphohistiocytosis Type2 Due to PRF1 Mutation in Chinese Pediatric Patients.

Familial hemophagocytic lymphohistiocytosis Type 2 (FHL2) associated central nervous system (CNS) involvement is less understood in children, especially when considering neurologic manifestations as part of the initial presentation. We conducted a retrospective review of the clinical manifestations and genetic abnormality of four Han Chinese children with FHL2 who were patients at the neurology department of Beijing Children's Hospital from November 2015 to October 2018. These four patients initially manifested CNS symptoms in their disease presentation, and all four patients were misdiagnosed as having ademyelinating disease, such as acute disseminated encephalomyelitis and multiple sclerosis. Given these misdiagnoses, it is important that general physicians and pediatricians maintain awareness of the possibility of FHL2 as a differential diagnosis. These four cases included neurologic manifestations including seizures, ataxia, spasticity, gait disorder, and coma. Bilateral abnormal signals in the cerebrum, including in white matter, gray matter, and junctions were discovered. Enhanced magnetic resonance imaging (MRI) in these patients showed spot or ring enhancement and/or hemorrhage. These patients all possessed a compound heterozygote mutation PRF1 gene. Whole exome sequencing analysis revealed seven different mutations (three novel mutations) spread over the PRF1 gene and a heterozygous missense mutation c.1349C > T [p.T450M] that was present in two patients. Three novel mutations, c.634T > C[p.Y212H], c.1083_1094del[p.361_364del], and c.1306G > T [p.D436Y], were discovered and through in silico analysis were discovered to be deleterious. Neurologic manifestations were the initial symptoms of FHL2 in these patients in addition to the expected leukopenia and hepatosplenomegaly. Whole exome sequencing of PRF1 for patients with similar presentations would facilitate prompt and accurate diagnosis and treatment.

[Reversible ceftriaxone-associated biliary pseudolithiasis in three children with renal diseases].

OBJECTIVE: To study the clinical characteristics of ceftriaxone-associated biliary pseudolithiasis in children with renal diseases. METHOD: Three children with renal diseases developed biliary pseudolithiasis when they were treated with ceftriaxone. Their clinical and laboratory data were retrospectively analyzed. RESULTS: Case one was an 11-year-old boy. The initial diagnosis was primary nephrotic syndrome. Ceftriaxone was administered intravenously at a dose of 2 g/d [50 mg/(kg * d)] for gastroenteritis. After that the boy complained of nausea and loss of appetite. Abdominal sonogram obtained on day 3 of ceftriaxone therapy revealed gallbladder sludge. After cessation of ceftriaxone treatment, symptoms and ultrasound abnormalities gradually disappeared, with complete sonographic resolution after 16 days. Case two was a 10-year-old boy. The primary diagnosis was post-streptococcal glomerulonephritis with acute renal failure. The child was treated with 1.5 g/d [30 mg/(kg * d)] intravenous ceftriaxone for gastroenteritis. After that, the boy complained of nausea and abdominal pain with positive Murphy's sign. Gallstone was detected by ultrasonographic examination on day 6 of ceftriaxone therapy. After cessation of ceftriaxone treatment, symptoms and sonographic abnormalities gradually disappeared, with complete sonographic resolution after 18 days. Case three was a 12-year-old boy. The primary diagnosis was nephrotic syndrome. He was treated with 2 g/d [40 mg/(kg.d)] ceftriaxone for gastroenteritis. Gallbladder lithiasis was detected 17 days after the initiation of ceftriaxone therapy (3 days after cessation of ceftriaxone treatment). Gallbladder sonogram was found to be normal two months after the discontinuation of the therapy. CONCLUSIONS: Biliary pseudolithiasis occurred in 3 cases with renal diseases receiving low doses of ceftriaxone. The risk of developing ceftriaxone-associated biliary pseudolithiasis might increase in patients with renal diseases who are treated with ceftriaxone.