Short- and long-delay consolidation of memory accessibility and precision across childhood and young adulthood

Childhood is a period when memory consolidation and knowledge base undergo rapid changes. The present study examined short-delay (overnight) and long-delay (after a 2-week period) consolidation of new information either congruent or incongruent with prior knowledge in typically developing 6- to 8-year-old children (n = 32), 9- to 11-year-old children (n = 33), and 18- to 30-year-old young adults (YA; n = 39). Both memory accessibility (cued recall of objects) and precision (precision of object placement) of initially well-learned object-scene pairs were measured. Our results showed that overnight, memory accessibility declined similarly in all age groups; memory precision improved more in younger children (YC) compared to older children (OC) and even declined in YA. After a 2-week period, both memory accessibility and precision became worse. Specifically, while age groups showed similar decline in memory accessibility, precision decline was less in YC than in OC and YA. The accessibility and precision of congruent and incongruent information changed similarly with consolidation in all age groups. Taken together, our results showed that, for initially well-learned information, YC have robust memory consolidation, despite their overall lower mnemonic performance compared to OC and YA, which is potentially crucial for stable and precise knowledge accumulation early on in development. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Analysis of bihemispheric language function in pediatric neurosurgical patients using repetitive navigated transcranial magnetic stimulation

OBJECTIVE

Language dominance in the developing brain can vary widely across anatomical and pathological conditions as well as age groups. Repetitive navigated transcranial magnetic stimulation (rnTMS) has been applied to calculate the hemispheric dominance ratio (HDR) in adults. In this study, the authors aimed to assess the feasibility of using rnTMS to identify language lateralization in a pediatric neurosurgical cohort and to correlate the preoperative rnTMS findings with the postoperative language outcome.

METHODS

A consecutive prospectively collected cohort of 19 children with language-associated lesions underwent bihemispheric rnTMS mapping prior to surgery (100 stimulation sites on each hemisphere). In addition to feasibility and adverse effects, the HDR (ratio of the left hemisphere to right hemisphere error rate) was calculated. The anatomical surgical site and postoperative language outcome at 3 months after surgery were assessed according to clinical documentation.

RESULTS

Repetitive nTMS mapping was feasible in all 19 children (mean age 12.5 years, range 4-17 years; 16 left-sided lesions) without any relevant adverse events. Thirteen children (68%) showed left hemispheric dominance (HDR > 1.1), and 2 children (11%) showed right hemispheric dominance (HDR < 0.9). In 4 children (21%), the bihemispheric error rates were nearly the same (HDR ≥ 0.9 and ≤ 1.1). Sixteen children underwent surgery (14 tumor/lesion resections and 2 hemispherotomies) and 3 patients continued conservative therapy. After surgery, 4 patients (25%) showed an improvement in language function, 10 (63%) presented with stable language function, and 2 (12.5%) experienced deterioration in language function. Of the 6 patients with right hemispheric language involvement, 4 (80%) had glial tumors, 1 (20%) had focal cortical dysplasia, and 1 (20%) experienced hypoxic brain injury. Children with right hemispheric language involvement (HDR ≤ 1.1) did not show any language deterioration postoperatively.

CONCLUSIONS

Bihemispheric rnTMS language mapping as a noninvasive mapping technique to assess lateralization of language function in the pediatric neurosurgical population is safe and feasible. Why relevant right hemispheric language function (HDR ≤ 1.1) was associated with postoperative unaltered language function needs to be validated in future studies. Bihemispheric rnTMS language mapping strengthens risk-benefit considerations prior to pediatric tumor/epilepsy surgery in language-associated areas.

The importance of routine genetic testing in pediatric epilepsy surgery

Genetic variants in relevant genes coexisting with MRI lesions in children with drug-resistant epilepsy (DRE) can negatively influence epilepsy surgery outcomes. Still, presurgical evaluation does not include genetic diagnostics routinely. Here, we report our presurgical evaluation algorithm that includes routine genetic testing. We analyzed retrospectively the data of 68 children with DRE operated at a mean age of 7.8 years (IQR: 8.1 years) at our center. In 49 children, genetic test results were available. We identified 21 gene variants (ACMG III: n = 7, ACMG IV: n = 2, ACMG V: n = 12) in 19 patients (45.2%) in the genes TSC1, TSC2, MECP2, DEPDC5, HUWE1, GRIN1, ASH1I, TRIO, KIF5C, CDON, ANKD11, TGFBR2, ATN1, COL4A1, JAK2, KCNQ2, ATP1A2, and GLI3 by whole-exome sequencing as well as deletions and duplications by array CGH in six patients. While the results did not change the surgery indication, they supported counseling with respect to postoperative chance of seizure freedom and weaning of antiseizure medication (ASM). The presence of genetic findings leads to the postoperative retention of at least one ASM. In our cohort, the International League against Epilepsy (ILAE) seizure outcome did not differ between patients with and without abnormal genetic findings. However, in the 7/68 patients with an unsatisfactory ILAE seizure outcome IV or V 12 months postsurgery, 2 had an abnormal or suspicious genetic finding as a putative explanation for persisting seizures postsurgery, and 3 had received palliative surgery including one TSC patient. This study highlights the importance of genetic testing in children with DRE to address putative underlying germline variants as genetic epilepsy causes or predisposing factors that guide patient and/or parent counseling on a case-by-case with respect to their individual chance of postoperative seizure freedom and ASM weaning. PLAIN LANGUAGE SUMMARY: Genetic variants in children with drug-resistant epilepsy (DRE) can negatively influence epilepsy surgery outcomes. However, presurgical evaluation does not include genetic diagnostics routinely. This retrospective study analyzed the genetic testing results of the 68 pediatric patients who received epilepsy surgery in our center. We identified 21 gene variants by whole-exome sequencing as well as deletions and duplications by array CGH in 6 patients. These results highlight the importance of genetic testing in children with DRE to guide patient and/or parent counseling on a case-by-case with respect to their individual chance of postoperative seizure freedom and ASM weaning.

The impact of microbiota and ketogenic diet interventions in the management of drug-resistant epilepsy

AIM

Drug-resistant epilepsy (DRE) is a neurological disorder characterized by uncontrolled seizures. It affects between 10%-40% of the patients with epilepsy worldwide. Drug-resistant patients have been reported to have a different microbiota composition compared to drug-sensitive patients and healthy controls. Importantly, fecal microbiota transplantations (FMTs), probiotic and dietary interventions have been shown to be able to reduce seizure frequency and improve the quality of life in drug-resistant patients. The classic ketogenic diet (KD) and its modifications may reduce seizures in DRE in some patients, whereas in others they do not. The mechanisms mediating the dietary effects remain elusive, although it is known that gut microbes play an important role in transmitting dietary effects to the host. Indeed, specific commensal microbes differ even between responders and non-responders to KD treatment.

METHODS

In this narrative mini-review, we summarize what is known about the gut microbiota changes and ketogenic diets with special focus on patients with DRE.

RESULTS AND CONCLUSIONS

By highlighting unanswered questions and by suggesting future research directions, we map the route towards future improvement of successful DRE therapy.

PTRH2 is Necessary for Purkinje Cell Differentiation and Survival and its Loss Recapitulates Progressive Cerebellar Atrophy and Ataxia Seen in IMNEPD Patients

Hom ozygous variants in the peptidyl-tRNA hydrolase 2 gene (PTRH2) cause infantile-onset multisystem neurologic, endocrine, and pancreatic disease. The objective is to delineate the mechanisms underlying the core cerebellar phenotype in this disease. For this, we generated constitutive (Ptrh2LoxPxhCMVCre, Ptrh2-/- mice) and Purkinje cell (PC) specific (Ptrh2LoxPxPcp2Cre, Ptrh2ΔPCmice) Ptrh2 mutant mouse models and investigated the effect of the loss of Ptrh2 on cerebellar development. We show that Ptrh2-/- knockout mice had severe postnatal runting and lethality by postnatal day 14. Ptrh2ΔPC PC specific knockout mice survived until adult age; however, they showed progressive cerebellar atrophy and functional cerebellar deficits with abnormal gait and ataxia. PCs of Ptrh2ΔPC mice had reduced cell size and density, stunted dendrites, and lower levels of ribosomal protein S6, a readout of the mammalian target of rapamycin pathway. By adulthood, there was a marked loss of PCs. Thus, we identify a cell autonomous requirement for PTRH2 in PC maturation and survival. Loss of PTRH2 in PCs leads to downregulation of the mTOR pathway and PC atrophy. This suggests a molecular mechanism underlying the ataxia and cerebellar atrophy seen in patients with PTRH2 mutations leading to infantile-onset multisystem neurologic, endocrine, and pancreatic disease.

Real-world experience with cenobamate: A systematic review and meta-analysis

PURPOSE

Despite many new ASM, the rate of patients with drug-resistant epilepsy (DRE) has not changed. Cenobamate (CNB) is a novel ASM for the treatment of focal-onset seizures in adults with high seizure freedom rates in randomized controlled trials (RCT). Although CNB appears to be effective, it is not commonly prescribed to patients with DRE, resulting in a lack of "real-world data".

METHODS

To evaluate the real-world effect of CNB and to assess the generalizability of RCT data, a systematic review and meta-analysis was conducted. Pooled proportions were calculated using a random intercept logistic regression model.

RESULTS

The analysis included seven studies with a total of 229 patients with DRE, 77.3 % of whom were adults and 91.5 % had focal-onset seizures. Seizure reduction >50 % was achieved in 68 % of patients [54.54; 79.07], with seizure freedom in 16.2 % [8.38; 28.97]. There was no difference between pediatric and adult patients. CNB was discontinued in 10 % [6.74; 14.6] of patients, mostly due to lack of efficacy (39 %) or adverse effects (AE, 43 %). AE, observed in 57.3 % [39.7; 73.2] of patients, included fatigue and vertigo. A comparison of the rates calculated in this meta-analysis to the active arm of equivalent RCTs revealed no significant difference.

CONCLUSION

CNB achieves a good treatment response in patients with DRE in real-world settings, like the effect reported in RCTs. The high heterogeneity between studies calls for studies focusing on specific DRE subpopulations.

Synapsin autoantibodies during pregnancy are associated with fetal abnormalities

Anti-neuronal autoantibodies can be transplacentally transferred during pregnancy and may cause detrimental effects on fetal development. It is unclear whether autoantibodies against synapsin-I, one of the most abundant synaptic proteins, are associated with developmental abnormalities in humans. We recruited a cohort of 263 pregnant women and detected serum synapsin-I IgG autoantibodies in 13.3% using cell-based assays. Seropositivity was strongly associated with abnormalities of fetal development including structural defects, intrauterine growth retardation, amniotic fluid disorders and neuropsychiatric developmental diseases in previous children (odds ratios of 3-6.5). Autoantibodies reached the fetal circulation and were mainly of IgG1/IgG3 subclasses. They bound to conformational and linear synapsin-I epitopes, five distinct epitopes were identified using peptide microarrays. The findings indicate that synapsin-I autoantibodies may be clinically useful biomarkers or even directly participate in the disease process of neurodevelopmental disorders, thus being potentially amenable to antibody-targeting interventional strategies in the future.

Pediatric de novo movement disorders and ataxia in the context of SARS-CoV-2

OBJECTIVE

In the fourth year of the COVID-19 pandemic, mortality rates decreased, but the risk of neuropsychiatric disorders remained the same, with a prevalence of 3.8% of pediatric cases, including movement disorders (MD) and ataxia.

METHODS

In this study, we report on a 10-year-old girl with hemichorea after SARS-CoV-2 infection and immunostained murine brain with patient CSF to identify intrathecal antibodies. Additionally, we conducted a scoping review of children with MD and ataxia after SARS-CoV-2 infection.

RESULTS

We detected antibodies in the patient's CSF binding unknown antigens in murine basal ganglia. The child received immunosuppression and recovered completely. In a scoping review, we identified further 32 children with de novo MD or ataxia after COVID-19. While in a minority of cases, MD or ataxia were a symptom of known clinical entities (e.g. ADEM, Sydenham's chorea), in most children, the etiology was suspected to be of autoimmune origin without further assigned diagnosis. (i) Children either presented with ataxia (79%), but different from the well-known postinfectious acute cerebellar ataxia (older age, less favorable outcome, or (ii) had hypo-/hyperkinetic MD (21%), which were choreatic in most cases. Besides 14% of spontaneous recovery, immunosuppression was necessary in 79%. Approximately one third of children only partially recovered.

CONCLUSIONS

Infection with SARS-CoV-2 can trigger de novo MD in children. Most patients showed COVID-19-associated-ataxia and fewer-chorea. Our data suggest that patients benefit from immunosuppression, especially steroids. Despite treatment, one third of patients recovered only partially, which makes up an increasing cohort with neurological sequelae.

Epilepsy surgery in early infancy: A retrospective, multicenter study

Although epilepsy surgery is the only curative therapeutic approach for lesional drug-resistant epilepsy (DRE), there is reluctance to operate on infants due to a fear of complications. A recent meta-analysis showed that epilepsy surgery in the first 6 months of life can achieve seizure control in about two thirds of children. However, robust data on surgical complications and postoperative cognitive development are lacking. We performed a retrospective multicenter study of infants who underwent epilepsy surgery in the first 6 months of life. 15 infants underwent epilepsy surgery at a median age of 134 days (IQR: 58) at four centers. The most common cause was malformation of cortical development, and 13 patients underwent a hemispherotomy. Two thirds required intraoperative red blood transfusions. Severe intraoperative complications occurred in two patients including death in one infant due to cardiovascular insufficiency. At a median follow-up of 1.5 years (IQR: 1.8), 57% of patients were seizure-free. Three patients where reoperated at a later age, resulting in 79% seizure freedom. Anti-seizure medication could be reduced in two thirds, and all patients improved in their development. Our findings suggest that early epilepsy surgery can result in good seizure control and developmental improvement. However, given the perioperative risks, it should be performed only in specialized centers.

Treatment of pediatric convulsive status epilepticus

Status epilepticus is one of the most common life-threatening neurological emergencies in childhood with the highest incidence in the first 5 years of life and high mortality and morbidity rates. Although it is known that a delayed treatment and a prolonged seizure can cause permanent brain damage, there is evidence that current treatments may be delayed and the medication doses administered are insufficient. Here, we summarize current knowledge on treatment of convulsive status epilepticus in childhood and propose a treatment algorithm. We performed a structured literature search via PubMed and ClinicalTrails.org and identified 35 prospective and retrospective studies on children <18 years comparing two and more treatment options for status epilepticus. The studies were divided into the commonly used treatment phases. As a first-line treatment, benzodiazepines buccal/rectal/intramuscular/intravenous are recommended. For status epilepticus treated with benzodiazepine refractory, no superiority of fosphenytoin, levetirazetam, or phenobarbital was identified. There is limited data on third-line treatments for refractory status epilepticus lasting >30 min. Our proposed treatment algorithm, especially for children with SE, is for in and out-of-hospital onset aids to promote the establishment and distribution of guidelines to address the treatment delay aggressively and to reduce putative permanent neuronal damage. Further studies are needed to evaluate if these algorithms decrease long-term damage and how to treat refractory status epilepticus lasting >30 min.

WWOX developmental and epileptic encephalopathy: Understanding the epileptology and the mortality risk

OBJECTIVE

WWOX is an autosomal recessive cause of early infantile developmental and epileptic encephalopathy (WWOX-DEE), also known as WOREE (WWOX-related epileptic encephalopathy). We analyzed the epileptology and imaging features of WWOX-DEE, and investigated genotype-phenotype correlations, particularly with regard to survival.

METHODS

We studied 13 patients from 12 families with WWOX-DEE. Information regarding seizure semiology, comorbidities, facial dysmorphisms, and disease outcome were collected. Electroencephalographic (EEG) and brain magnetic resonance imaging (MRI) data were analyzed. Pathogenic WWOX variants from our cohort and the literature were coded as either null or missense, allowing individuals to be classified into one of three genotype classes: (1) null/null, (2) null/missense, (3) missense/missense. Differences in survival outcome were estimated using the Kaplan-Meier method.

RESULTS

All patients experienced multiple seizure types (median onset = 5 weeks, range = 1 day-10 months), the most frequent being focal (85%), epileptic spasms (77%), and tonic seizures (69%). Ictal EEG recordings in six of 13 patients showed tonic (n = 5), myoclonic (n = 2), epileptic spasms (n = 2), focal (n = 1), and migrating focal (n = 1) seizures. Interictal EEGs demonstrated slow background activity with multifocal discharges, predominantly over frontal or temporo-occipital regions. Eleven of 13 patients had a movement disorder, most frequently dystonia. Brain MRIs revealed severe frontotemporal, hippocampal, and optic atrophy, thin corpus callosum, and white matter signal abnormalities. Pathogenic variants were located throughout WWOX and comprised both missense and null changes including five copy number variants (four deletions, one duplication). Survival analyses showed that patients with two null variants are at higher mortality risk (p-value = .0085, log-rank test).

SIGNIFICANCE

Biallelic WWOX pathogenic variants cause an early infantile developmental and epileptic encephalopathy syndrome. The most common seizure types are focal seizures and epileptic spasms. Mortality risk is associated with mutation type; patients with biallelic null WWOX pathogenic variants have significantly lower survival probability compared to those carrying at least one presumed hypomorphic missense pathogenic variant.

Retrospective Pediatric Cohort Study Validates NEOS Score and Demonstrates Applicability in Children With Anti-NMDAR Encephalitis

BACKGROUND AND OBJECTIVES

Anti-N-methyl-D-aspartate receptor encephalitis (NMDARE) is the most common form of autoimmune encephalitis in children and adults. Although our understanding of the disease mechanisms has progressed, little is known about estimating patient outcomes. Therefore, the NEOS (anti-NMDAR Encephalitis One-Year Functional Status) score was introduced as a tool to predict disease progression in NMDARE. Developed in a mixed-age cohort, it currently remains unclear whether NEOS can be optimized for pediatric NMDARE.

METHODS

This retrospective observational study aimed to validate NEOS in a large pediatric-only cohort of 59 patients (median age of 8 years). We reconstructed the original score, adapted it, evaluated additional variables, and assessed its predictive power (median follow-up of 20 months). Generalized linear regression models were used to examine predictability of binary outcomes based on the modified Rankin Scale (mRS). In addition, neuropsychological test results were investigated as alternative cognitive outcome.

RESULTS

The NEOS score reliably predicted poor clinical outcome (mRS ≥3) in children in the first year after diagnosis (p = 0.0014) and beyond (p = 0.036, 16 months after diagnosis). A score adapted to the pediatric cohort by adjusting the cutoffs of the 5 NEOS components did not improve predictive power. In addition to these 5 variables, further patient characteristics such as the "Herpes simplex virus encephalitis (HSE) status" and "age at disease onset" influenced predictability and could potentially be useful to define risk groups. NEOS also predicted cognitive outcome with higher scores associated with deficits of executive function (p = 0.048) and memory (p = 0.043).

DISCUSSION

Our data support the applicability of the NEOS score in children with NMDARE. Although not yet validated in prospective studies, NEOS also predicted cognitive impairment in our cohort. Consequently, the score could help identify patients at risk of poor overall clinical outcome and poor cognitive outcome and thus aid in selecting not only optimized initial therapies for these patients but also cognitive rehabilitation to improve long-term outcomes.

Is There a Cognitive Decline in Pediatric Patients Following Epilepsy Surgery?

BACKGROUND

Epilepsy surgery is currently the only way to cure drug-resistant epilepsy (DRE). The loss of epileptic activity or its propagation in the developing brain may not only result in seizure freedom but also be associated with further positive effects. Here, we analyzed the cognitive development of children and adolescents with DRE after epilepsy surgery.

METHODS

We evaluated retrospectively the cognitive development of children and adolescents before and after epilepsy surgery.

RESULTS

Fifty-three children and adolescents underwent epilepsy surgery at a median age of 7.62 years. Overall seizure freedom was 86.8% at a current median observation period of 20 months. Presurgically, 81.1% had the clinical diagnosis of cognitive impairment, which was confirmed by standardized tests in 43 of 53 patients (76.7%). Further 10 patients had severe cognitive impairment rendering a standardized test impossible. The median intelligence quotient (IQ)/development quotient value was 74. After surgery, caretakers reported developmental progress in all patients, whereas the median IQ decreased slightly (P = 0.404). In eight patients the IQ points decreased after surgery; however, their individual raw scores increased in line with their reported increase in cognitive abilities.

CONCLUSIONS

We did not detect any cognitive deterioration in children following epilepsy surgery. A loss of IQ points did not correspond to a real loss of cognitive abilities. These patients developed more slowly than age-matched peers with an average development speed but profited individually as seen in their raw scores. Therefore, an individual analysis of raw scores is relevant to assess the cognitive development after surgery.

Primidone improves symptoms in TRPM3-linked DEE-SWAS

Developmental and epileptic encephalopathy (DEE) with continuous spike-and-wave activation in sleep (CSWS) or DEE-SWAS is an age-dependent disease, often accompanied by a decline in cognitive abilities. Early successful treatment of CSWS is associated with a better cognitive outcome. We retrospectively analyzed the clinical, electrophysiological, radiological, and genetic data of children with DEE-SWAS associated with melastatin-related transient receptor type 3 gene (TRPM3) missense variants. We report two unrelated children with pharmaco-resistant DEE-SWAS and developmental delay/regression and different heterozygous de novo missense variants in the TRPM3 gene (NM_001366145.2; c.3397T>C/p.Ser1133Pro, c.2004G>A/p.Val1002Met). The variant p.Val1002Met (previously known as p.Val990Met or p.Val837Met) and p.Ser1133Pro were recently shown to result in a gain-of-function (GoF) effect. Based on this fact, previous drug resistance, and the experimentally demonstrated inhibitory effect of primidone on TRPM3, we initiated an individualized therapy with this drug. In both children, developmental regression was stopped, psychomotor development improved, and CSWS was no longer detectable. To our knowledge, this is the first report of a treatment with primidone in TRPM3-associated CSWS. Our results highlight the importance of early genetic diagnosis in patients with epilepsy and the possibility of precision medicine, which should be considered in future individuals with a TRPM3-linked DEE-SWAS.

Family Burden and Epilepsy Surgery in Children with Drug-Resistant Epilepsy

INTRODUCTION

 Family burden (FB) in pediatric patients with drug-resistant epilepsy (DRE) is significantly higher than that in children with non-DRE. Epilepsy surgery is an established approach to treat DRE, and this study examines the impact of pediatric epilepsy surgery on FB.

METHODS

 We retrospectively analyzed data of families and pediatric patients with focal structural DRE treated with epilepsy surgery at our epilepsy center from April 2018 to November 2021. We examined the relationship between cognitive, behavioral, and epilepsy-specific data and the FB measured with the German version of the Impact on Family Scale before and after epilepsy surgery.

RESULTS

 The study cohort included 31 children with DRE at a mean age of 9 years at surgery (range = 0-16) and a mean epilepsy duration of 3 years (range = 0-14). Cognitive impairment correlated with FB in children with DRE prior to surgery. At the last assessment, 14.5 months (mean, range = 6-24) after epilepsy surgery, 87.2% of patients were seizure-free, FB values had decreased by 75.0%, and behavioral problems had decreased by 85,7%. Cognitive functions remained stable following epilepsy surgery.

CONCLUSION

 In children with DRE, epilepsy surgery reduces FB. Given the considerable impact of families on the development and wellbeing of their children, the impact of epilepsy surgery should be communicated to affected families.

Corticosteroids in childhood epilepsies: A systematic review

Corticosteroids have been used for the treatment of patients with epilepsy for more than 6 decades, based on the hypothesis of inflammation in the genesis and/or promotion of epilepsy. We, therefore, aimed to provide a systematic overview of the use of corticosteroid regimes in childhood epilepsies in line with the PRISMA guidelines. We performed a structured literature search via PubMed and identified 160 papers with only three randomized controlled trials excluding the substantial trials on epileptic spasms. Corticosteroid regimes, duration of treatment (days to several months), and dosage protocols were highly variable in these studies. Evidence supports the use of steroids in epileptic spasms; however, there is only limited evidence for a positive effect for other epilepsy syndromes, e.g., epileptic encephalopathy with spike-and-wave activity in sleep [(D)EE-SWAS] or drug-resistant epilepsies (DREs). In (D)EE-SWAS (nine studies, 126 patients), 64% of patients showed an improvement either in the EEG or in their language/cognition following various steroid treatment regimes. In DRE (15 studies, 436 patients), a positive effect with a seizure reduction in 50% of pediatric and adult patients and seizure freedom in 15% was identified; however, no recommendation can be drawn due to the heterozygous cohort. This review highlights the immense need for controlled studies using steroids, especially in DRE, to offer patients new treatment options.

Proteome changes in autosomal recessive primary microcephaly

BACKGROUND/AIM

Autosomal recessive primary microcephaly (MCPH) is a rare and genetically heterogeneous group of disorders characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. MCPH3 is caused by biallelic variants in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the corresponding Cdk5rap2 mutant or Hertwig's anemia mouse model, congenital microcephaly as well as defects in the hematopoietic system, germ cells and eyes have been reported. The reduction in brain volume, particularly affecting gray matter, has been attributed mainly to disturbances in the proliferation and survival of early neuronal progenitors. In addition, defects in dendritic development and synaptogenesis exist that affect the excitation-inhibition balance. Here, we studied proteomic changes in cerebral cortices of Cdk5rap2 mutant mice.

MATERIAL AND METHODS

We used large-gel two-dimensional gel (2-DE) electrophoresis to separate cortical proteins. 2-DE gels were visualized by a trained observer on a light box. Spot changes were considered with respect to presence/absence, quantitative variation and altered mobility.

RESULT

We identified a reduction in more than 30 proteins that play a role in processes such as cell cytoskeleton dynamics, cell cycle progression, ciliary functions and apoptosis. These proteome changes in the MCPH3 model can be associated with various functional and morphological alterations of the developing brain.

CONCLUSION

Our results shed light on potential protein candidates for the disease-associated phenotype reported in MCPH3.

Case report: Compound heterozygous NUP85 variants cause autosomal recessive primary microcephaly

Nucleoporin (NUP) 85 is a member of the Y-complex of nuclear pore complex (NPC) that is key for nucleocytoplasmic transport function, regulation of mitosis, transcription, and chromatin organization. Mutations in various nucleoporin genes have been linked to several human diseases. Among them, NUP85 was linked to childhood-onset steroid-resistant nephrotic syndrome (SRNS) in four affected individuals with intellectual disability but no microcephaly. Recently, we broaden the phenotype spectrum of NUP85-associated disease by reporting NUP85 variants in two unrelated individuals with primary autosomal recessive microcephaly (MCPH) and Seckel syndrome (SCKS) spectrum disorders (MCPH-SCKS) without SRNS. In this study, we report compound heterozygous NUP85 variants in an index patient with only MCPH phenotype, but neither Seckel syndrome nor SRNS was reported. We showed that the identified missense variants cause reduced cell viability of patient-derived fibroblasts. Structural simulation analysis of double variants is predicted to alter the structure of NUP85 and its interactions with neighboring NUPs. Our study thereby further expands the phenotypic spectrum of NUP85-associated human disorder and emphasizes the crucial role of NUP85 in the brain development and function.

Real-world data on cannabidiol treatment of various epilepsy subtypes: A retrospective, multicenter study

OBJECTIVE

Cannabidiol (CBD) is approved for treatment of Dravet syndrome (DS), Lennox-Gastaut syndrome (LGS), and tuberous sclerosis complex (TSC). Several studies suggest antiseizure effects also beyond these three epilepsy syndromes.

METHODS

In a retrospective multicenter study, we analyzed the efficacy and tolerability of CBD in patients with epilepsy at 16 epilepsy centers.

RESULTS

The study cohort comprised 311 patients with epilepsy with a median age of 11.3 (0-72) years (235 children and adolescents, 76 adults). Therapy with CBD was off-label in 91.3% of cases due to age, epilepsy subtype, lack of adjunct therapy with clobazam, and/or higher dose applied. CBD titration regimens were slower than recommended, with good tolerability of higher doses particularly in children. Of all patients, 36.9% experienced a reduction in seizure frequency of >50%, independent of their epilepsy subtype or clobazam co-medication. The median observation period was 15.8 months. About one third of all patients discontinued therapy within the observation period due to adverse effects or lack of efficacy. Adverse effects were reported frequently (46.9%).

SIGNIFICANCE

Our study highlights that CBD has an antiseizure effect comparable to other antiseizure medications with a positive safety profile independent of the epilepsy subtype. Comedication with clobazam was not associated with a better outcome. Higher doses to achieve seizure frequency reduction were safe, particularly in children. These findings call for further trials for an extended approval of CBD for other epilepsy subtypes and for children <2 years of age.

Gain-of-function variants in the ion channel gene TRPM3 underlie a spectrum of neurodevelopmental disorders

TRPM3 is a temperature- and neurosteroid-sensitive plasma membrane cation channel expressed in a variety of neuronal and non-neuronal cells. Recently, rare de novo variants in TRPM3 were identified in individuals with developmental and epileptic encephalopathy, but the link between TRPM3 activity and neuronal disease remains poorly understood. We previously reported that two disease-associated variants in TRPM3 lead to a gain of channel function . Here, we report a further 10 patients carrying one of seven additional heterozygous TRPM3 missense variants. These patients present with a broad spectrum of neurodevelopmental symptoms, including global developmental delay, intellectual disability, epilepsy, musculo-skeletal anomalies, and altered pain perception. We describe a cerebellar phenotype with ataxia or severe hypotonia, nystagmus, and cerebellar atrophy in more than half of the patients. All disease-associated variants exhibited a robust gain-of-function phenotype, characterized by increased basal activity leading to cellular calcium overload and by enhanced responses to the neurosteroid ligand pregnenolone sulfate when co-expressed with wild-type TRPM3 in mammalian cells. The antiseizure medication primidone, a known TRPM3 antagonist, reduced the increased basal activity of all mutant channels. These findings establish gain-of-function of TRPM3 as the cause of a spectrum of autosomal dominant neurodevelopmental disorders with frequent cerebellar involvement in humans and provide support for the evaluation of TRPM3 antagonists as a potential therapy.

Case report: KPTN gene-related syndrome associated with a spectrum of neurodevelopmental anomalies including severe epilepsy

Biallelic variants in the kaptin gene KPTN were identified recently in individuals with a novel syndrome referred to as autosomal recessive intellectual developmental disorder 41 (MRT41). MRT41 is characterized by developmental delay, predominantly in language development, behavioral abnormalities, and epilepsy. Only about 15 affected individuals have been described in the literature, all with primary or secondary macrocephaly. Using exome sequencing, we identified three different biallelic variants in KPTN in five affected individuals from three unrelated families. In total, two KPTN variants were already reported as a loss of function variants. A novel splice site variant in KPTN was detected in two unrelated families of this study. The core phenotype with neurodevelopment delay was present in all patients. However, macrocephaly was not present in at least one patient. In total, two patients exhibited developmental and epileptic encephalopathies with generalized tonic-clonic seizures that were drug-resistant in one of them. Thus, we further delineate the KPTN-related syndrome, especially emphasizing the severity of epilepsy phenotypes and difficulties in treatment in patients of our cohort.

Telemedicine in Neuromuscular Diseases During Covid-19 Pandemic: ERN-NMD European Survey

BACKGROUND

Telemedicine (TM) contributes to bridge the gap between healthcare facilities and patients' homes with neuromuscular disease (NMD) because of mobility issues. However, its deployment is limited due to difficulties evaluating subtle neurological signs such as mild weakness or sensory deficits. The COVID-19 pandemic has disrupted healthcare delivery worldwide, necessitating rapid measures implementation by health care providers (HCPs) to protect patients from acquiring SARS-CoV-2 while maintaining the best care and treatment.

OBJECTIVES

Given the challenges faced by remote healthcare assistance of NMD patients, we aim to evaluate the use of TM in NMD during the COVID-19 pandemic.

METHODS

Based on the Model for Assessment-of-Telemedicine-Applications (MAST), we conducted a survey amongst clinicians of the ERN EURO NMD (European-Reference-Network-for-Rare-Neuromuscular-Diseases).

RESULTS

Based on 42 responses over 76 expected ones, our results show that the COVID-19 pandemic significantly increased the number of HCPs using TM (from 60% to 100%). The TM types most used during the COVID-19 period are teleconsultation and consultation by phone, particularly in the context of symptoms worsening in NMD patients with COVID-19 infection. Most European HCPs were satisfied when using TM but as a complementary option to physical consultations. Many responses addressed the issue of technical aspects needing improvement, particularly for elderly patients who need caregivers' assistance for accessing the TM platform.

CONCLUSIONS

TM has been essential during COVID-19, but its use still presents some limitations for NMD patients with cognitive deficits or for first-time diagnosis. Thus, TM should be used as complement to, rather than substitute, for face-to-face consultations.

Maternal synapsin autoantibodies are associated with neurodevelopmental delay

Maternal autoantibodies can be transmitted diaplacentally, with potentially deleterious effects on neurodevelopment. Synapsin 1 (SYN1) is a neuronal protein that is important for synaptic communication and neuronal plasticity. While monoallelic loss of function (LoF) variants in the SYN1 gene result in X-linked intellectual disability (ID), learning disabilities, epilepsy, behavioral problems, and macrocephaly, the effect of SYN1 autoantibodies on neurodevelopment remains unclear. We recruited a clinical cohort of 208 mothers and their children with neurologic abnormalities and analyzed the role of maternal SYN1 autoantibodies. We identified seropositivity in 9.6% of mothers, and seropositivity was associated with an increased risk for ID and behavioral problems. Furthermore, children more frequently had epilepsy, macrocephaly, and developmental delay, in line with the SYN1 LoF phenotype. Whether SYN1 autoantibodies have a direct pathogenic effect on neurodevelopment or serve as biomarkers requires functional experiments.

Monoallelic CRMP1 gene variants cause neurodevelopmental disorder

Collapsin response mediator proteins (CRMPs) are key for brain development and function. Here, we link CRMP1 to a neurodevelopmental disorder. We report heterozygous de novo variants in the CRMP1 gene in three unrelated individuals with muscular hypotonia, intellectual disability, and/or autism spectrum disorder. Based on in silico analysis these variants are predicted to affect the CRMP1 structure. We further analyzed the effect of the variants on the protein structure/levels and cellular processes. We showed that the human CRMP1 variants impact the oligomerization of CRMP1 proteins. Moreover, overexpression of the CRMP1 variants affect neurite outgrowth of murine cortical neurons. While altered CRMP1 levels have been reported in psychiatric diseases, genetic variants in CRMP1 gene have never been linked to human disease. We report for the first-time variants in the CRMP1 gene and emphasize its key role in brain development and function by linking directly to a human neurodevelopmental disease.

Successful treatment of adult Dravet syndrome patients with cenobamate

Dravet syndrome (DS) is a rare, drug-resistant, severe developmental and epileptic encephalopathy caused by pathogenic variants in the α subunit of the voltage-gated sodium channel gene SCN1A. Hyperexcitability in DS results from loss of function in inhibitory interneurons. Thus sodium channel blockers are usually contraindicated in patients with DS as they may lead to disease aggravation. Cenobamate (CNB) is a novel antiseizure medication (ASM) with promising rates of seizure freedom in patients with focal-onset, drug-resistant epilepsy. CNB blocks persistent sodium currents by promoting the inactive states of sodium channels. In a multi-center study, we analyzed retrospectively the effect of an add-on therapy of CNB in adult patients with DS. We report four adult patients with DS in whom the use of CNB resulted in a significant seizure reduction of more than 80%, with a follow-up of up to 542 days. CNB was the first drug in these patients that resulted in a long-lasting and significant seizure reduction. No severe adverse events occurred. We highlight CNB as an ASM that may lead to a clinically meaningful reduction of seizure frequency in adult patients with DS. It is unclear, however, if all patients with DS benefit, requiring further investigation and functional experiments.

Importance of urodynamic evaluation of bladder function after secondary untethering in spina bifida patients: single center experience of 30 years

INTRODUCTION

A TCS after primary closure of meningomyeloceles is a known complication of the spina bifida disease. Data on the outcome after SSCU surgery is heterogeneous and lacking standardization. Thus we aimed to find a reliable system for assessment of the bladder function before and after SSCU surgery and document postoperative outcome.

METHODS

A retrospective study was performed on a cohort of patients with spina bifida diagnosis. In total, 130 patients underwent 182 SSCU surgeries, 56 of those met our inclusion criteria. A classification system, including two different methods, was used. The AC system used baseline pressure and detrusor over activity to define three levels of bladder dysfunction, the second method ranked the severity of bladder dysfunction by awarding points from 0 to 2 for bladder capacity, maximal detrusor pressure during autonomous contractions, leak point pressure and vesicoureteral reflux A high score is correlated with a severe bladder dysfunction.

RESULTS

Gender distribution was equally (male: n = 29; 51.8%; female: n = 27; 48.2%). The median age at SSCU was 902 years (range 0.5-22.8 years). After SSCU, the stage improved in 11 patients (19.6%), worsened in 11 (19.6%) patients and remained the same in 34 patients (60.7%) after intervention (AC score). Non-worsening was observed in a total of 45 cases (80.4%) (p < 0.001). MHS score (n = 27, 48.2%) improved, remained unchanged (n = 12, 21.4%), 17 patients worsened (30.4%). Non-worsening in postoperative bladder functional outcome was demonstrated in 39 cases (69.6%) over all (p < 0.005). Regardless of whether bladder function is categorized by AC or MHS, postoperative outcome worsened significantly when SSCU was performed due to increasing deterioration in motor function alone (p < 0.05). Of the 24 cases with NOD as indication, 22 (91.7%) had an unchanged (n = 10; 41.7%) or improved (n = 12; 50.0%), meaning positive neuro-orthopedic outcome, only 2 (8.3%) deteriorated (p < 0.001).

CONCLUSION

Our study presents reliable evaluation systems for bladder function in spina bifida patients. Since indications for SSCU surgery differ, it is important to know the possible effects on bladder function after this surgical procedure. Even a mild impairment of bladder function has a risk to deteriorate after SSCU surgery. Particularly interesting becomes this with regard to the fact that the prevalence of TCS might become more frequent with the rising numbers of prenatal closures of meningomyeloceles.

Case report: Expanding the phenotype of ARHGEF17 mutations from increased intracranial aneurysm risk to a neurodevelopmental disease

RhoGTPase regulators play a key role in the development of the nervous system, and their dysfunction can result in brain malformation and associated disorders. Several guanine nucleotide exchange factors (GEF) have been linked to neurodevelopmental disorders. In line with this, ARHGEF17 has been recently linked as a risk gene to intracranial aneurysms. Here we report siblings of a consanguineous Pakistani family with biallelic variants in the ARHGEF17 gene associated with a neurodevelopmental disorder with intellectual disability, speech delay and motor dysfunction but not aneurysms. Cranial MRI performed in one patient revealed generalized brain atrophy with an enlarged ventricular system, thin corpus callosum and microcephaly. Whole exome sequencing followed by Sanger sequencing in two of the affected individuals revealed a homozygous missense variant (g.11:73021307, c.1624C>T (NM_014786.4), p.R542W) in the ARHGEF17 gene. This variant is in a highly conserved DCLK1 phosphorylation consensus site (I/L/V/F/M]RRXX[pS/pT][I/L/M/V/F) of the protein. Our report expands the phenotypic spectrum of ARHGEF17 variants from increased intracranial aneurysm risk to neurodevelopmental disease and thereby add ARHGEF17 to the list of GEF genes involved in neurodevelopmental disorders.

Real-World Experience Treating Pediatric Epilepsy Patients With Cenobamate

Introduction

In one third of all patients with epilepsy, seizure freedom is not achieved through anti-seizure medication (ASM). These patients have an increased risk of earlier death, poorer cognitive development, and reduced quality of life. Cenobamate (CNB) has recently been approved as a promising novel ASM drug for the treatment of adults with focal-onset epilepsy. However, there is little experience for its application in pediatric patients.

Methods

In a multicenter study we evaluated retrospectively the outcome of 16 pediatric patients treated “off label” with CNB.

Results

In 16 patients with a mean age of 15.38 years, CNB was started at an age of 15.05 years due to DRE. Prior to initiation of therapy, an average of 10.56 (range 3–20) ASM were prescribed. At initiation, patients were taking 2.63 (range 1–4) ASM. CNB was increased by 0.47 ± 0.27mg/kg/d every 2 weeks with a mean maximum dosage of 3.1 mg/kg/d (range 0.89–7) and total daily dose of 182.81 mg (range 50–400 mg). Seizure freedom was achieved in 31.3% and a significant seizure reduction of >50% in 37.5%. Adverse events occurred in 10 patients with fatigue/somnolence as the most common. CNB is taken with high adherence in all but three patients with a median follow-up of 168.5 days

Conclusion

Cenobamate is an effective ASM for pediatric patients suffering from drug-resistant epilepsy. In addition to excellent seizure reduction or freedom, it is well-tolerated. Cenobamate should be considered as a novel treatment for DRE in pediatric patients.

β-Ureidopropionase deficiency due to novel and rare UPB1 mutations affecting pre-mRNA splicing and protein structural integrity and catalytic activity

β-Ureidopropionase is the third enzyme of the pyrimidine degradation pathway and catalyses the conversion of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid to β-alanine and β-aminoisobutyric acid, ammonia and CO₂. To date, only a limited number of genetically confirmed patients with a complete β-ureidopropionase deficiency have been reported. Here, we report on the clinical, biochemical and molecular findings of 10 newly identified β-ureidopropionase deficient individuals. Patients presented mainly with neurological abnormalities and markedly elevated levels of N-carbamyl-β-alanine and N-carbamyl-β-aminoisobutyric acid in urine. Analysis of UPB1, encoding β-ureidopropionase, showed 5 novel missense variants and two novel splice-site variants. Functional expression of the UPB1 variants in mammalian cells showed that recombinant ß-ureidopropionase carrying the p.Ala120Ser, p.Thr129Met, p.Ser300Leu and p.Asn345Ile variant yielded no or significantly decreased β-ureidopropionase activity. Analysis of the crystal structure of human ß-ureidopropionase indicated that the point mutations affect substrate binding or prevent the proper subunit association to larger oligomers and thus a fully functional β-ureidopropionase. A minigene approach showed that the intronic variants c.[364 + 6 T > G] and c.[916 + 1_916 + 2dup] led to skipping of exon 3 and 8, respectively, in the process of UPB1 pre-mRNA splicing. The c.[899C > T] (p.Ser300Leu) variant was identified in two unrelated Swedish β-ureidopropionase patients, indicating that β-ureidopropionase deficiency may be more common than anticipated.

Selenium Status in Paediatric Patients with Neurodevelopmental Diseases

Neurodevelopmental diseases are often associated with other comorbidities, especially inflammatory processes. The disease may affect the trace element (TE) status, which in turn may affect disease severity and progression. Selenium (Se) is an essential TE required for the biosynthesis of selenoproteins including the transporter selenoprotein P (SELENOP) and extracellular glutathione peroxidase (GPX3). SELENOP deficiency in transgenic mice resulted in a Se status-dependent phenotype characterized by impaired growth and disturbed neuronal development, with epileptic seizures on a Se-deficient diet. Therefore, we hypothesized that Se and SELENOP deficiencies may be prevalent in paediatric patients with a neurodevelopmental disease. In an exploratory cross-sectional study, serum samples from children with neurodevelopmental diseases (n = 147) were analysed for total serum Se, copper (Cu), and zinc (Zn) concentrations as well as for the TE biomarkers SELENOP, ceruloplasmin (CP), and GPX3 activity. Children with epilepsy displayed elevated Cu and Zn concentrations but no dysregulation of serum Se status. Significantly reduced SELENOP concentrations were found in association with intellectual disability (mean ± SD (standard deviation); 3.9 ± 0.9 mg/L vs. 4.4 ± 1.2 mg/L, p = 0.015). A particularly low GPX3 activity (mean ± SD; 172.4 ± 36.5 vs. 192.6 ± 46.8 U/L, p = 0.012) was observed in phacomatoses. Autoantibodies to SELENOP, known to impair Se transport, were not detected in any of the children. In conclusion, there was no general association between Se deficiency and epilepsy in this observational analysis, which does not exclude its relevance to individual cases. Sufficiently high SELENOP concentrations seem to be of relevance to the support of normal mental development. Decreased GPX3 activity in phacomatoses may be relevant to the characteristic skin lesions and merits further analysis. Longitudinal studies are needed to determine whether the observed differences are relevant to disease progression and whether correcting a diagnosed TE deficiency may confer health benefits to affected children.

Standard values for MRI brain biometry throughout the first year of life

BACKGROUND

Brain structures in the infant brain are investigated reliably using cranial magnetic resonance imaging. However, the lack of quantitative standard values for various brain regions results in data interpretation that is often subjective or based on small patient cohorts. The aim of this study was to create simple linear measurements to assess brain structures in infancy.

METHODS

We assessed cranial magnetic resonance imaging sessions of 131 children without intracerebral pathology retrospectively for size of various brain structures throughout the first year of life.

RESULTS

Standard values for the size and the growth rate of 14 brain structures including lateral ventricles, frontal subarachnoid space, pons, medulla oblongata, cerebellar vermis, pituitary gland, optical nerve, corpus callosum and the tegmentovermian angle were defined.

CONCLUSION

Our study offers reference values for the biometric assessment of the infant brain. Especially in children with multiple brain malformations, it is essential to know the normal absolute and relative size of brain structures.

Modified Zipper Method, a Promising Treatment Option in Severe Pediatric Immune-Mediated Neurologic Disorders

OBJECTIVE

To introduce and evaluate a modified version of the "zipper method"-a treatment strategy alternating intravenous immunoglobulin (IVIG) and plasma exchange (PLEX) first reported for 9 pediatric cases of Guillain-Barré syndrome in 2018-for treatment of severe immune-mediated neurologic disorders in children.

METHODS

The modified zipper method comprised longer intervals between PLEX-IVIG cycles (48 hours instead of 24 hours), more cycles (7-10 instead of 5), a consistent plasma volume exchange (instead of the original multistep approach), and variable infusion times for IVIGs (4-8 hours). The modified zipper method was applied as an individual treatment approach once standard therapy failed. The follow-up ranged from 6 months to 2 years. Cases were analyzed retrospectively. Disease severity was mainly quantified by the Guillain-Barré syndrome disability score.

RESULTS

Four children (9-15 years) with (1) Miller-Fisher syndrome, (2) Bickerstaff brainstem encephalitis, (3) common Guillain-Barré syndrome, and (4) severe acute disseminated encephalomyelitis were treated by the modified zipper method. Results for duration of mechanical ventilation (median of 12 days, interquartile range [IQR] 8-16), hospital stay (median of 23 days, IQR 22-24), and time to unaided walking (median of 22 days, IQR 21-37) outperformed previous studies with IVIG/PLEX alone or IVIG + PLEX combinations unlike the zipper method.

CONCLUSION

The modified zipper method is associated with a low mortality, a short mechanical ventilation time, a short hospital stay, and an excellent outcome in children with severe Guillain-Barré syndrome or acute disseminated encephalomyelitis. Our regimen is streamlined for applicability. Results emphasize its robust effectiveness as an option for therapy escalation in severe neuroimmunologic diseases. Now, multicenter trials are needed to evaluate this novel treatment strategy.

Cerebral Abnormalities in Spina Bifida: A Neuropathological Study

INTRODUCTION

Spina bifida (SB) is the most common neural tube defect in humans. Here, we analyzed systematically the neuropathological findings of the brain in SB cases.

METHODS

79 cases with SB aperta (SBA) and 6 cases with SB occulta (SBO) autopsied at the Charité Neuropathology from 1974 to 2000 were re-evaluated retrospectively. For this, case files and spinal cord as well as brain sections were studied.

RESULTS

While no brain malformations were detected in SBO cases, 95% of SBA cases had brain malformations. Main brain anomalies identified were hydrocephalus (71%), Chiari II malformation (36%), heterotopia (34%), other cerebellar anomalies (36%), gyrification defects (33%), and ependymal denudation (29%). Hydrocephalus was observed as early as gestational week 17 and was highly associated to Chiari II and ependymal denudation. In 55% SBA was accompanied by further anomalies not primarily affecting the CNS.

CONCLUSION

We confirm using neuropathologic methods brain malformations in most SBA but none in SBO cases. In addition to our previous radiologic study, we now demonstrate the high prevalence of cerebellar malformations and cerebral heterotopias in SBA. The early detection of hydrocephalus and Chiari II malformation in fetuses raises the question whether these arise parallel rather than in strict temporal sequence.

Is cannabidiol worth a trial in Rasmussen encephalitis?

We report 3 patients (age 8, 13 and 14 years) with drug-resistant epilepsy due to Rasmussen encephalitis treated with cannabidiol in addition to their current antiseizure medication (ASM). In all three patients we observed a positive effect, which seemed to surpass the efficacy that would be expected from a different fourth or fifth antiseizure drug used during the course of the disease.

Relationship between cerebral palsy severity and cognition, aids and education

BACKGROUND

Cerebral palsy (CP) refers to a non-progressive permanent lesion of the developing brain, which can manifest with motor function disability and various comorbidities and complications. However, there is little data on the correlation between motor and mental function in CP, as cognitive assessments are rarely the main focus of studies on children with CP.

METHODS

We studied a large cohort of 381 children and adolescents with CP. We analyzed the relationship between severity of CP and the presence of developmental disturbances (motor, motor-linguistic, global) including cognition, the number of aids and education.

RESULTS

We found a strong correlation between the severity of CP according to the Gross Motor Function Classification System (GMFCS) and developmental disturbances. In line with this finding, the number of aids per individual also correlated significantly with CP severity and the extent of developmental disturbance. Going beyond the number of aids most patients already received special education in kindergarten. Later, the type of schooling correlated significantly with severity of CP and developmental disturbance. While developmental disturbance and cognition correlated, this was not the case for CP severity and cognition. The latter indicates a wide range in individual manifestation and resources.

CONCLUSIONS

Our data underline that cognition does not necessarily correlate with CP severity. Thus, in addition to the evaluation and treatment of motor deficits, cognitive assessment should be offered early-on to improve patient-centered counselling and support with respect to appropriate education.

Cross-sectional, Neuromuscular Phenotyping Study of Arhinia Patients With SMCHD1 Variants

BACKGROUND AND OBJECTIVES

Facioscapulohumeral muscular dystrophy type 2 (FSHD2) and arhinia are two distinct disorders caused by pathogenic variants in the same gene, SMCHD1. The mechanism underlying this phenotypic divergence remains unclear. In this study, we characterize the neuromuscular phenotype of individuals with arhinia caused by SMCHD1 variants and analyze their complex genetic and epigenetic criteria to assess their risk for FSHD2.

METHODS

Eleven individuals with congenital nasal anomalies, including arhinia, nasal hypoplasia, or anosmia, underwent a neuromuscular exam, genetic testing, muscle ultrasound, and muscle MRI. Risk for FSHD2 was determined by combined genetic and epigenetic analysis of 4q35 haplotype, D4Z4 repeat length and methylation profile. We also compared expression levels of pathogenic DUX4 mRNA in primary myoblasts or dermal fibroblasts (upon myogenic differentiation or epigenetic transdifferentiation, respectively) in these individuals to those with confirmed FSHD2.

RESULTS

Among the eleven individuals with rare, pathogenic, heterozygous missense variants in exons 3-11 of SMCHD1, only a subset (n=3/11; 1 male, 2 females; age 25-51 years) met the strict genetic and epigenetic criteria for FSHD2 (D4Z4 repeat unit length <21 in cis with a 4qA haplotype, and D4Z4 methylation <30%). None of the 3 individuals had typical clinical manifestations or muscle imaging findings consistent with FSHD2. However, the arhinia patients meeting the permissive genetic and epigenetic criteria for FSHD2 displayed some DUX4 expression in dermal fibroblasts under the epigenetic de-repression by drug treatment and in the primary myoblasts undergoing myogenic differentiation.

DISCUSSION

In this cross-sectional study, we identified arhinia patients who meet the full genetic and epigenetic criteria for FSHD2 and display the molecular hallmark of FSHD, that is DUX4 de-repression and expression in vitro, but who do not manifest with the typical clinicopathologic phenotype of FSHD2. The distinct dichotomy between FSHD2 and arhinia phenotypes despite an otherwise poised DUX4 locus implies the presence of novel disease-modifying factors that seem to operate as a "switch", resulting in one phenotype and not the other. Identification and further understanding of these disease-modifying factors will likely provide valuable insight with therapeutic implications for both diseases.

Beware of Neurotoxins in Common Plants: Water Hemlock Poisoning Presenting as Convulsive Status Epilepticus

BACKGROUND

Pediatric status epilepticus occurs in about 44/100.000 children per year with an unknown cause in about a third of patients. One cause can be the ingestion of plants containing toxins that target the central nervous system. Here we describe an ingestion of water hemlock resulting in a status epilepticus.

METHODS

We studied in detail the clinical, laboratory, electrophysiological, and radiological features of a patient with status epilepticus.

RESULTS

A 9-year-old boy presented to the pediatric emergency department for sudden onset of nausea, vomiting, and status epilepticus approximately one hour after the patient had bitten into the root of a water plant in an inner-city park. Bilateral tonic-clonic seizures could only be terminated after administration of midazolam, lorazepam, and finally propofol. Cranial MRI, cerebrospinal fluid, and EEG findings were largely unremarkable. The ingested plant was identified as water hemlock through a detailed search with the help of a drawing issued by the patient with the help of the medical team. The specific toxicological analysis for water hemlock verified the presence of cicutoxin and cicudiol in the blood sample. The patient was discharged, levetiracetam was weaned off four weeks later, and he has remained seizure free since.

CONCLUSIONS

Given the considerable percentage of cases of unknown etiology in new-onset pediatric status epilepticus, it is important to consider plant intoxication as a possible cause.

Clinical Phenotype of Cerebral Palsy Depends on the Cause: Is It Really Cerebral Palsy? A Retrospective Study

Cerebral palsy is the most common motor disability in childhood. Still, the precise definition in terms of causes and timing of the brain damage remains controversial. Several studies examine the clinical phenotype of cerebral palsy types. The aim of our study was to determine to what extent the clinical phenotype of cerebral palsy patients depends on the underlying cause. We retrospectively evaluated the clinical phenotype, abnormalities during pregnancy, and cerebral palsy cause of 384 patients, treated at Charité-Medicine University, between 2015 and 2017. The cause of cerebral palsy was identified in 79.9% of cases. Causes prior to the perinatal period were, compared to perinatal brain damage, associated significantly with different comorbidities. The term cerebral palsy does not describe a single disease but is an umbrella term covering many different diseases. Depending on the cause, a varying clinical phenotype can be found, which offers great potential in terms of individual treatment and preventing comorbidities.

Autosomal Recessive Primary Microcephaly: Not Just a Small Brain

Microcephaly or reduced head circumference results from a multitude of abnormal developmental processes affecting brain growth and/or leading to brain atrophy. Autosomal recessive primary microcephaly (MCPH) is the prototype of isolated primary (congenital) microcephaly, affecting predominantly the cerebral cortex. For MCPH, an accelerating number of mutated genes emerge annually, and they are involved in crucial steps of neurogenesis. In this review article, we provide a deeper look into the microcephalic MCPH brain. We explore cytoarchitecture focusing on the cerebral cortex and discuss diverse processes occurring at the level of neural progenitors, early generated and mature neurons, and glial cells. We aim to thereby give an overview of current knowledge in MCPH phenotype and normal brain growth.

Case Report: Hemispherotomy in the First Days of Life to Treat Drug-Resistant Lesional Epilepsy

Background: Neonatal drug-resistant epilepsy is often caused by perinatal epileptogenic insults such as stroke, ischemia, hemorrhage, and/or genetic defects. Rapid seizure control is particularly important for cognitive development. Since early surgical intervention and thus a short duration of epilepsy should lead to an optimal developmental outcome, we present our experience with hemispherotomy in an infant at the corrected age of 1 week.

Methods: We report successful hemispherotomy for drug-resistant epilepsy in an infant with hemimegalencephaly at a corrected age of 1 week.

Results: The infant was diagnosed with drug-resistant lesional epilepsy due to hemimegalencephaly affecting the left hemisphere. Given congruent electroclinical findings, we performed a left vertical parasagittal transventricular hemispherotomy after critical interdisciplinary discussion. No complications occurred during the surgery. Intraoperatively; 118 ml of red blood cells (30 ml/kg) and 80 ml of plasma were transfused. The patient has been seizure-free since discharge without further neurological deficits.

Conclusion: We demonstrate that early epilepsy surgery is a safe procedure in very young infants if performed in a specialized center experienced with age-specific surgical conditions and perioperative management. The specific surgical difficulties should be weighed against the risk of life-long developmental drawbacks of ongoing detrimental epilepsy.

Case Report: Behavioral Disorder Following Hemispherotomy: A Valproate Effect?

Background: Hemispherotomy is an epilepsy surgery procedure applied to cure particularly pharmacorefractory lesional epilepsy due to unihemispheric pathologies. Such a disconnection of an entire hemisphere is followed by reorganizational processes. Methods: We describe an acute aggravation of behavioral problems following a hemispherotomy in a patient treated with valproic acid, which subsided once valproate was discontinued. Results: A 9-year-old boy with drug-resistant epilepsy caused by the residua of a perinatal stroke treated for several years with valproic acid and lamotrigine underwent hemispherotomy. Shortly after surgery, minimal preoperative behavioral problems intensified dramatically, and aggression occurred as a new symptom. Assuming a correlation between valproate treatment and the postoperative altered neuronal network, we tapered off valproate. The behavioral problems decreased in intensity with the reduction of valproate dose and disappeared after drug discontinuation. Conclusion: We describe severe behavioral problems after hemispherotomy that subsided when valproate was tapered off. While we cannot rule out a spontaneous correction of a post-hemispherotomy network dysregulation, our report raises awareness to possible altered effects of the anticonvulsant valproic acid parallel to reorganizational processes after hemispherotomy.

Encephalitis patient-derived monoclonal GABAA receptor antibodies cause epileptic seizures

Autoantibodies targeting the GABAA receptor (GABAAR) hallmark an autoimmune encephalitis presenting with frequent seizures and psychomotor abnormalities. Their pathogenic role is still not well-defined, given the common overlap with further autoantibodies and the lack of patient-derived mAbs. Five GABAAR mAbs from cerebrospinal fluid cells bound to various epitopes involving the α1 and γ2 receptor subunits, with variable binding strength and partial competition. mAbs selectively reduced GABAergic currents in neuronal cultures without causing receptor internalization. Cerebroventricular infusion of GABAAR mAbs and Fab fragments into rodents induced a severe phenotype with seizures and increased mortality, reminiscent of encephalitis patients' symptoms. Our results demonstrate direct pathogenicity of autoantibodies on GABAARs independent of Fc-mediated effector functions and provide an animal model for GABAAR encephalitis. They further provide the scientific rationale for clinical treatments using antibody depletion and can serve as tools for the development of antibody-selective immunotherapies.

Gene replacement therapy with onasemnogene abeparvovec in children with spinal muscular atrophy aged 24 months or younger and bodyweight up to 15 kg: an observational cohort study

BACKGROUND

Given the novelty of gene replacement therapy with onasemnogene abeparvovec in spinal muscular atrophy, efficacy and safety data are limited, especially for children older than 24 months, those weighing more than 8·5 kg, and those who have received nusinersen. We aimed to provide real-world data on motor function and safety after gene replacement therapy in different patient subgroups.

METHODS

We did a protocol-based, multicentre prospective observational study between Sept 21, 2019, and April 20, 2021, in 18 paediatric neuromuscular centres in Germany and Austria. All children with spinal muscular atrophy types 1 and 2 receiving onasemnogene abeparvovec were included in our cohort, and there were no specific exclusion criteria. Motor function was assessed at the time of gene replacement therapy and 6 months afterwards, using the Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP INTEND) and Hammersmith Functional Motor Scale-Expanded (HFMSE) scores. Additionally, in children pretreated with nusinersen, motor function was assessed before and after treatment switch. Off-target adverse events were analysed with a focus on liver function, thrombocytopaenia, and potential cardiotoxicity.

FINDINGS

76 children (58 pretreated with nusinersen and 18 who were nusinersen naive) with spinal muscular atrophy were treated with onasemnogene abeparvovec at a mean age of 16·8 months (range 0·8-59·0, IQR 9-23) and a mean weight of 9·1 kg (range 4·0-15·0, IQR 7·4-10·6). In 60 patients with available data, 49 had a significant improvement on the CHOP-INTEND score (≥4 points) and HFMSE score (≥3 points). Mean CHOP INTEND scores increased significantly in the 6 months after therapy in children younger than 8 months (n=16; mean change 13·8 [SD 8·5]; p<0·0001) and children aged between 8 and 24 months (n=34; 7·7 [SD 5·2]; p<0·0001), but not in children older than 24 months (n=6; 2·5 [SD 5·2]; p=1·00). In the 45 children pretreated with nusinersen and had available data, CHOP INTEND score increased by 8·8 points (p=0·0003) at 6 months after gene replacement therapy. No acute complications occurred during infusion of onasemnogene abeparvovec, but 56 (74%) patients had treatment-related side-effects. Serious adverse events occurred in eight (11%) children. Liver enzyme elevation significantly increased with age and weight at treatment. Six (8%) patients developed acute liver dysfunction. Other adverse events included pyrexia (n=47 [62%]), vomiting or loss of appetite (41 [54%]), and thrombocytopenia (n=59 [78%]). Prednisolone treatment was significantly prolonged with a mean duration of 15·7 weeks (IQR 9-19), mainly due to liver enzyme elevation. Cardiac adverse events were rare; only two patients had abnormal echocardiogram and echocardiography findings.

INTERPRETATION

This study provides class IV evidence that children with spinal muscular atrophy aged 24 months or younger and patients pretreated with nusinersen significantly benefit from gene replacement therapy, but adverse events can be severe and need to be closely monitored.

FUNDING

None.

TRANSLATION

For the German translation of the abstract see Supplementary Materials section.

Infratentorial MRI Findings in Rasmussen Encephalitis Suggest Primary Cerebellar Involvement

Background and Objective

Rasmussen encephalitis (RE) is characterized by its unilateral cerebral involvement. However, both ipsi- and contralesional cerebellar atrophy have been anecdotally reported raising questions about the nature and extent of infratentorial findings. Using MRI, we morphometrically investigated the cerebellum and hypothesized abnormalities beyond the effects of secondary atrophy, implicating a primary involvement of the cerebellum by RE.

Methods

Voxel-based morphometry of the cerebellum and brainstem was conducted in 57 patients with RE and in 57 matched controls. Furthermore, patient-specific asymmetry indices (AIs) of cerebellar morphometry and fluid-attenuated inversion recovery (FLAIR) intensity were calculated. Using diffusion tensor imaging, the integrity of the cortico-ponto-cerebellar (CPC) tract was assessed. Finally, a spatial independent component analysis (ICA) was used to compare atrophy patterns between groups.

Results

Patients with RE showed bilateral cerebellar and predominantly ipsilesional mesencephalic atrophy (p < 0.01). Morphometric AIs revealed ipsilesional < contralesional asymmetry in 27 and ipsilesional > contralesional asymmetry in 30 patients. In patients with predominant ipsilesional atrophy, morphometric AIs strongly correlated with FLAIR intensity AIs (r = 0.86, p < 0.0001). Fractional anisotropy was lower for ipsilesional-to-contralesional CPC tracts than opposite tracts (T = 2.30, p < 0.05). ICA revealed bilateral and strictly ipsi- and contralesional atrophy components in patients with RE (p < 0.05).

Discussion

We demonstrated atrophy of the ipsilesional-to-contralesional CPC pathway and, consequently, interpret the loss of contralesional gray matter as secondary crossed cerebellar atrophy. The ipsilesional cerebellar atrophy, however, defies this explanation. Based on FLAIR hyperintensities, we interpret ipsilesional atrophy to be due to inflammation in the scope of a primary involvement of the cerebellum by RE.

Lessons learned from drug trials in neurofibromatosis: A systematic review

Neurofibromatosis (NF) is the umbrella term for neurofibromatosis type 1 (NF1), neurofibromatosis type 2 (NF2) and schwannomatosis (SWN). EU-PEARL aims to create a framework for platform trials in NF. The aim of this systematic review is to create an overview of recent clinical drug trials in NF, to identify learning points to guide development of the framework. We searched Embase, Medline and Cochrane register of trials on October 1, 2020 for publications of clinical drug trials in NF patients. We excluded publications published before 2010, systematic reviews, secondary analyses and studies with <10 patients. Data was extracted on manifestations studied, study design, phase, number of participating centres and population size. Full-text review resulted in 42 articles: 31 for NF1, 11 for NF2, none for SWN. Most NF1 trials focused on plexiform neurofibromas (32%). Trials in NF2 solely studied vestibular schwannomas. In NF1, single-arm trials (58%) were most common, and the majority was phase II (74%). For NF2 most trials were single-arm (55%) and exclusively phase II. For both diseases, trials were predominantly single-country and included five centres or less. Study population sizes were small, with the majority including ≤50 patients (74%). In conclusion, NF research is dominated by studies on a limited number out of the wide range of manifestations. We need more trials for cutaneous manifestations and high-grade gliomas in NF1, manifestations other than vestibular schwannoma in NF2 and trials for SWN. Drug development in NF may profit from innovative trials on multiple interventions and increased international collaboration.

Evaluation of Metabolic Effects of Nusinersen in Patients with Spinal Muscular Atrophy

Nusinersen is the first disease-modifying therapy for spinal muscular atrophy (SMA), but there are few data on potential long-term endocrinological and metabolic systemic effects of this novel treatment as well as metabolic alterations in SMA itself. In this retrospective and multicentric study, we analyzed anthropometric, endocrinological, and motor function data of 81 pediatric and adult patients with SMA1 to 3 undergoing treatment with nusinersen. In 39 patients (51%), we observed a slight increase in body mass index (BMI) centiles under treatment with nusinersen, especially in patients with SMA2 and in pediatric patients between 3.1 and 12 years. A correlation to the SMN2 copy number or motor function was not found. Additionally, length centiles decreased significantly under treatment. The results of longitudinal endocrinological assessments were interpreted as not clinically significant in most patients; in three patients, the signs of an altered glucose metabolism were present. Our study indicates a putative effect of treatment with nusinersen on BMI, which might be due to a conjoint effect of weight gain and reduction of height velocity, without evidence of correlation to increased muscle function. Further studies need to address specific effects of targeted therapies such as nusinersen or onasemnogene abeparvovec on body composition including fat and muscle mass.