Rituximab for Pediatric Central Nervous System Inflammatory Disorders in Alberta, Canada.

BACKGROUND: Early and effective treatment of central nervous system (CNS) inflammatory disorders is vital to reduce neurologic morbidity and improve long-term outcomes in affected children. Rituximab is a B-cell-depleting monoclonal antibody whose off-label use for these disorders is funded in the province of Alberta, Canada, by the Short-Term Exceptional Drug Therapy (STEDT) program. This study describes the use of rituximab for pediatric CNS inflammatory disorders in Alberta. METHODS: Rituximab applications for CNS inflammatory indications in patients <18 years of age were identified from the STEDT database between January 1, 2012, and December 31, 2019. Patient information was linked to other provincial datasets including the Discharge Abstract Database, Pharmaceutical Information Network, and Provincial Laboratory data. Analysis was descriptive. RESULTS: Fifty-one unique rituximab applications were identified, of which 50 were approved. New applications increased from one in 2012 to a high of 12 in 2018. The most common indication was autoimmune encephalitis without a specified antibody (n = 16, 31%). Most children were approved for a two-dose (n = 33, 66%) or four-dose (n = 16, 32%) induction regimen. Physician-reported outcomes were available for 24 patients, of whom 14 (58%) were felt to have fully met outcome targets. CONCLUSION: The use of rituximab for pediatric CNS inflammatory disorders has increased, particularly for the indication of autoimmune encephalitis. This study identified significant heterogeneity in dosing practices and laboratory monitoring. Standardized protocols for the use of rituximab in these disorders and more robust outcome reporting will help better define the safety and efficacy of rituximab in this population.

ARF1-related disorder: phenotypic and molecular spectrum.

PURPOSE: ARF1 was previously implicated in periventricular nodular heterotopia (PVNH) in only five individuals and systematic clinical characterisation was not available. The aim of this study is to provide a comprehensive description of the phenotypic and genotypic spectrum of ARF1-related neurodevelopmental disorder. METHODS: We collected detailed phenotypes of an international cohort of individuals (n=17) with ARF1 variants assembled through the GeneMatcher platform. Missense variants were structurally modelled, and the impact of several were functionally validated. RESULTS: De novo variants (10 missense, 1 frameshift, 1 splice altering resulting in 9 residues insertion) in ARF1 were identified among 17 unrelated individuals. Detailed phenotypes included intellectual disability (ID), microcephaly, seizures and PVNH. No specific facial characteristics were consistent across all cases, however microretrognathia was common. Various hearing and visual defects were recurrent, and interestingly, some inflammatory features were reported. MRI of the brain frequently showed abnormalities consistent with a neuronal migration disorder. CONCLUSION: We confirm the role of ARF1 in an autosomal dominant syndrome with a phenotypic spectrum including severe ID, microcephaly, seizures and PVNH due to impaired neuronal migration.

Fetal hippocampal development: analysis by magnetic resonance imaging volumetry.

The hippocampal formation plays an important role in learning and memory; however, data on its development in utero in humans are limited. This study was performed to evaluate hippocampal development in healthy fetuses using 3D reconstructed MRI. A cohort of 20 healthy pregnant women underwent prenatal MRI at a median GA of 24.9 wk (range, 21.3-31.9 wk); six of the women also had a second fetal MRI performed at a 6-wk interval. Routine 2D ultrafast T2-weighted images were used to reconstruct a 3D volume image, which was then used to manually segment the right and left hippocampi. Total hippocampal volume was calculated for each subject and compared against GA. There was a linear increase in total hippocampal volume with increasing GA (p < 0.001). For subjects scanned twice, there was an increase in hippocampal size on the second fetal MRI (p = 0.0004). This represents the first volumetric study of fetal hippocampal development in vivo. This normative volumetric data will be helpful for future comparison studies of suspected developmental abnormalities of hippocampal structure and function.

Patterns of Brain Injury in Perinatal Arterial Ischemic Stroke and the Development of Infantile Spasms.

INTRODUCTION: Perinatal arterial ischemic stroke (PAIS) underlies approximately 10% of infantile spasms (IS). We aim to identify patterns of brain injury in ischemic stroke that may predispose infants to infantile spasms. METHODS: Sixty-four perinatal arterial ischemic stroke patients were identified meeting the following inclusion criteria: term birth, magnetic resonance imaging (MRI) showing ischemic stroke or encephalomalacia in an arterial distribution, and follow-up records. Patients who developed infantile spasms (PAIS-IS) were analyzed descriptively for ischemic stroke injury patterns and were compared to a seizure-free control group (PAIS-only). Stroke injury was scored using the modified pediatric ASPECTS (modASPECTS). RESULTS: The PAIS-IS (n = 9) group had significantly higher modASPECTS than the PAIS-only (n = 16) group (P = .002, Mann-Whitney). A greater proportion of PAIS-IS patients had injury to deep cerebral structures (67%) than PAIS-only (25%). CONCLUSION: Infarct size was significantly associated with infantile spasms development. Results support theories implicating deep cerebral structures in infantile spasms pathogenesis. This may help identify perinatal arterial ischemic stroke patients at risk of infantile spasms, facilitating more timely diagnosis.

Clinical characteristics of pediatric myasthenia: a surveillance study.

OBJECTIVE: To evaluate the incidence, clinical features, diagnostic, and treatment trends of pediatric myasthenia in Canada. METHODS: Through established Canadian Pediatric Surveillance Program methodology, physicians were anonymously surveyed for cases of pediatric myasthenia using a standardized clinical questionnaire containing deidentified data. Inclusion criteria were any child <18 years old with ≥1 of the following: (1) fluctuating ptosis or extraocular weakness, (2) skeletal muscle weakness or fatigue, and (3) any of the following supportive tests: clinical response to acetylcholinesterase inhibitor, positive antibodies, abnormal slow repetitive nerve stimulation, or single-fiber electromyography. RESULTS: In 2 years of surveillance, 57 confirmed cases were reported. There were 34 generalized and 18 ocular reports of juvenile myasthenia gravis plus 5 congenital myasthenic syndrome cases. There were 14 incident cases in 2010 and 6 in 2011. Age of onset ranged from "birth" to 17 years for the generalized form compared with 18 months to 11 years for the ocular subtype. Positive acetylcholine receptor titers were found in 22 (67%) of 33 generalized cases and 8 (44%) of 18 ocular patients. Of patients started on pyridostigmine, improvement was noted in 33 (100%) of 33 generalized cases and 15 (88%) of 17 ocular cases. CONCLUSIONS: This study represents the largest descriptive series of pediatric myasthenia in North America and provides valuable information about clinical characteristics. A high index of suspicion is important for this treatable disease. Children generally respond promptly to readily available therapies.

Case of infantile onset spinocerebellar ataxia type 5.

Dominant spinocerebellar ataxias are a rare clinically and genetically heterogeneous group of neurodegenerative disorders. They are characterized by progressive cerebellar ataxia resulting in unsteady gait, clumsiness, dysarthria, and swallowing difficulty. The onset of symptoms is usually in the third or fourth decade of life; however, more subtle clinical manifestations can start in early childhood. Spinocerebellar ataxia type 5, a dominant spinocerebellar ataxia associated with mutations involving ß-III spectrin (SPTBN2), has been described in 3 families. It typically consists of a slowly progressive spinocerebellar ataxia with onset in the third decade. The authors present the first case of infantile-onset spinocerebellar ataxia associated with a novel SPTBN2 mutation (transition C>T at nucleotide position 1438), the proband having a much more severe phenotype with global developmental delay, hypotonia, tremor, nystagmus, and facial myokymia.

Rearrangement of chromosome 14q with associated white matter disease.

We report the case of a 29-month-old boy with spasticity and periventricular white matter changes on magnetic resonance imaging in whom a complex rearrangement consisting of a de novo duplication of 14q32.31q32.33 and deletion of 14q32.33 was identified by array-based comparative genomic hybridization. Our case replicates some of the previous features associated with chromosome 14q duplication and deletion while expanding its clinical spectrum with pyramidal tract dysfunction signs and neuroimaging features. Genomic lesions should be considered in cases of leukodystrophies, and genome-wide studies such as array-based comparative genomic hybridization could be considered in the assessment of undefined white matter disorders.

Atypical Rett syndrome with selective FOXG1 deletion detected by comparative genomic hybridization: case report and review of literature.

Rett syndrome is a severe neurodegenerative disorder characterized by acquired microcephaly, communication dysfunction, psychomotor regression, seizures and stereotypical hand movements. Mutations in methyl CpG binding protein 2 (MECP2) are identified in most patients with classic Rett syndrome. Genetic studies in patients with a Rett variant have expanded the spectrum of underlying genetic etiologies. Recently, a deletion encompassing several genes in the long arm of chromosome 14 has been associated with the congenital Rett-syndrome phenotype. Using array-based comparative genomic hybridization, we identified a 3-year-old female with a Rett-like syndrome carrying a de novo single-gene deletion of FOXG1. Her presentation included intellectual disability, epilepsy and a Rett-like phenotype. The variant features included microcephaly at birth and prominent synophrys. Our results confirm that congenital Rett syndrome can be caused by copy-number variation in FOXG1 and expand the clinical phenotypic spectrum of FOXG1 defect in humans.