De novo variants in RNF213 are associated with a clinical spectrum ranging from Leigh syndrome to early-onset stroke.

PURPOSE: RNF213, encoding a giant E3 ubiquitin ligase, has been recognized for its role as a key susceptibility gene for moyamoya disease. Case reports have also implicated specific variants in RNF213 with an early-onset form of moyamoya disease with full penetrance. We aimed to expand the phenotypic spectrum of monogenic RNF213-related disease and to evaluate genotype-phenotype correlations. METHODS: Patients were identified through reanalysis of exome sequencing data of an unselected cohort of unsolved pediatric cases and through GeneMatcher or ClinVar. Functional characterization was done by proteomics analysis and oxidative phosphorylation enzyme activities using patient-derived fibroblasts. RESULTS: We identified 14 individuals from 13 unrelated families with (de novo) missense variants in RNF213 clustering within or around the Really Interesting New Gene (RING) domain. Individuals presented either with early-onset stroke (n = 11) or with Leigh syndrome (n = 3). No genotype-phenotype correlation could be established. Proteomics using patient-derived fibroblasts revealed no significant differences between clinical subgroups. 3D modeling revealed a clustering of missense variants in the tertiary structure of RNF213 potentially affecting zinc-binding suggesting a gain-of-function or dominant negative effect. CONCLUSION: De novo missense variants in RNF213 clustering in the E3 RING or other regions affecting zinc-binding lead to an early-onset syndrome characterized by stroke or Leigh syndrome.

First detected geographical cluster of BoDV-1 encephalitis from same small village in two children: therapeutic considerations and epidemiological implications.

BACKGROUND: The Borna disease virus (BoDV-1) is an emerging zoonotic virus causing severe and mostly fatal encephalitis in humans. METHODS AND RESULTS: A local cluster of fatal BoDV-1 encephalitis cases was detected in the same village three years apart affecting two children. While the first case was diagnosed late in the course of disease, a very early diagnosis and treatment attempt facilitated by heightened awareness was achieved in the second case. Therapy started as early as day 12 of disease. Antiviral therapy encompassed favipiravir and ribavirin, and, after bioinformatic modelling, also remdesivir. As the disease is immunopathogenetically mediated, an intensified anti-inflammatory therapy was administered. Following initial impressive clinical improvement, the course was also fatal, although clearly prolonged. Viral RNA was detected by qPCR in tear fluid and saliva, constituting a possible transmission risk for health care professionals. Highest viral loads were found post mortem in the olfactory nerve and the limbic system, possibly reflecting the portal of entry for BoDV-1. Whole exome sequencing in both patients yielded no hint for underlying immunodeficiency. Full virus genomes belonging to the same cluster were obtained in both cases by next-generation sequencing. Sequences were not identical, indicating viral diversity in natural reservoirs. Specific transmission events or a common source of infection were not found by structured interviews. Patients lived 750m apart from each other and on the fringe of the settlement, a recently shown relevant risk factor. CONCLUSION: Our report highlights the urgent necessity of effective treatment strategies, heightened awareness and early diagnosis. Gaps of knowledge regarding risk factors, transmission events, and tailored prevention methods become apparent. Whether this case cluster reflects endemicity or a geographical hot spot needs further investigation.

Blood DNA methylation provides an accurate biomarker of KMT2B-related dystonia and predicts onset.

Dystonia is a prevalent, heterogeneous movement disorder characterized by involuntarily abnormal postures. Biomarkers of dystonia are notoriously lacking. Here, a biomarker is reported for histone lysine methyltransferase (KMT2B)-deficient dystonia, a leading subtype among the individually rare monogenic dystonias. It was derived by applying a support vector machine to an episignature of 113 DNA CpG sites, which, in blood cells, showed significant epigenome-wide association with KMT2B deficiency and at least 1× log-fold change of methylation. This classifier was accurate both when tested on the general population and on samples with various other deficiencies of the epigenetic machinery, thus allowing for definitive evaluation of variants of uncertain significance and identifying patients who may profit from deep brain stimulation, a highly successful treatment in KMT2B-deficient dystonia. Methylation was increased in KMT2B deficiency at all 113 CpG sites. The coefficients of variation of the normalized methylation levels at these sites also perfectly classified the samples with KMT2B-deficient dystonia. Moreover, the mean of the normalized methylation levels correlated well with the age at onset of dystonia (P = 0.003)-being lower in samples with late or incomplete penetrance-thus serving as a predictor of disease onset and severity. Similarly, it may also function in monitoring the recently envisioned treatment of KMT2B deficiency by inhibition of DNA methylation.

[Arterial ischemic stroke in childhood and adolescence : Time-critical emergency in pediatrics]. / Arteriell ischämischer Schlaganfall im Kindes- und Jugendalter : Zeitkritischer Notfall in der Pädiatrie.

Childhood arterial ischemic stroke is one of the most time-critical pediatric emergencies but is often diagnosed with a prognostically relevant time delay. The reasons are low awareness, sometimes unspecific clinical presentation with a wide variety of critical differential diagnoses and less coordinated acute care structures. The revascularization strategies established for adults also show sometimes spectacular success in children. These should therefore also be made available for affected children if possible, although the evidence is nowhere near comparable. In the postacute phase the etiological work-up is complex due to the risk factors which need to be considered, but identification of the individual risk profile is essential as it defines secondary prevention, risk of recurrence and outcome. The long-term care in a multiprofessional, interdisciplinary team must take into account all bio-psycho-social aspects of the child in the current developmental phase.

De novo variants in neurodevelopmental disorders-experiences from a tertiary care center.

Up to 40% of neurodevelopmental disorders (NDDs) such as intellectual disability, developmental delay, autism spectrum disorder, and developmental motor abnormalities have a documented underlying monogenic defect, primarily due to de novo variants. Still, the overall burden of de novo variants as well as novel disease genes in NDDs await discovery. We performed parent-offspring trio exome sequencing in 231 individuals with NDDs. Phenotypes were compiled using human phenotype ontology terms. The overall diagnostic yield was 49.8% (n = 115/231) with de novo variants contributing to more than 80% (n = 93/115) of all solved cases. De novo variants affected 72 different-mostly constrained-genes. In addition, we identified putative pathogenic variants in 16 genes not linked to NDDs to date. Reanalysis performed in 80 initially unsolved cases revealed a definitive diagnosis in two additional cases. Our study consolidates the contribution and genetic heterogeneity of de novo variants in NDDs highlighting trio exome sequencing as effective diagnostic tool for NDDs. Besides, we illustrate the potential of a trio-approach for candidate gene discovery and the power of systematic reanalysis of unsolved cases.

Real-life survey of pitfalls and successes of precision medicine in genetic epilepsies.

OBJECTIVE: The term 'precision medicine' describes a rational treatment strategy tailored to one person that reverses or modifies the disease pathophysiology. In epilepsy, single case and small cohort reports document nascent precision medicine strategies in specific genetic epilepsies. The aim of this multicentre observational study was to investigate the deeper complexity of precision medicine in epilepsy. METHODS: A systematic survey of patients with epilepsy with a molecular genetic diagnosis was conducted in six tertiary epilepsy centres including children and adults. A standardised questionnaire was used for data collection, including genetic findings and impact on clinical and therapeutic management. RESULTS: We included 293 patients with genetic epilepsies, 137 children and 156 adults, 162 females and 131 males. Treatment changes were undertaken because of the genetic findings in 94 patients (32%), including rational precision medicine treatment and/or a treatment change prompted by the genetic diagnosis, but not directly related to known pathophysiological mechanisms. There was a rational precision medicine treatment for 56 patients (19%), and this was tried in 33/56 (59%) and was successful (ie, >50% seizure reduction) in 10/33 (30%) patients. In 73/293 (25%) patients there was a treatment change prompted by the genetic diagnosis, but not directly related to known pathophysiological mechanisms, and this was successful in 24/73 (33%). SIGNIFICANCE: Our survey of clinical practice in specialised epilepsy centres shows high variability of clinical outcomes following the identification of a genetic cause for an epilepsy. Meaningful change in the treatment paradigm after genetic testing is not yet possible for many people with epilepsy. This systematic survey provides an overview of the current application of precision medicine in the epilepsies, and suggests the adoption of a more considered approach.

Next Generation Sequencing in Pediatric Epilepsy Using Customized Panels: Size Matters.

INTRODUCTION: Next generation sequencing (NGS) with customized gene panels is a helpful tool to identify monogenic epilepsy syndromes. The number of genes tested within a customized panel may vary greatly. The aim of the present study was to compare the diagnostic yield of small (<25 kb) and large (>25 kb) customized epilepsy panels. METHODS: This retrospective cohort study investigated data of 190 patients of 18 years or younger, with the diagnosis of an epilepsy of unknown etiology who underwent NGS using customized gene panels. Small (<25 kb) and large (>25 kb) panels were compared regarding the distribution of benign/likely benign and pathogenic/likely pathogenic variants and variants of unclear significance. In addition, differences of the diagnostic yield with respect to epilepsy severity, i.e., developmental and epileptic encephalopathy [DEE] vs. non-DEE, were analyzed. RESULTS: The diagnostic yield defined as pathogenic or likely pathogenic variants in large panels was significantly increased (29% [n = 14/48] vs. 13% [n = 18/142], p = 0.0198) compared with smaller panels. In non-DEE patients the increase of the diagnostic yield in large panels was significant(35% n = 6/17 vs. 13% n = 12/94, p = 0.0378), which was not true for DEE patients. DISCUSSION: This study indicates that large panels are superior for pediatric patients with epilepsy forms without encephalopathy (non-DEE). For patients suffering from DEE small panels of a maximum of 10 genes seem to be sufficient. The proportion of unclear findings increases with rising panel sizes. CONCLUSION: Customized epilepsy panels of >25 kb compared with smaller panels show a significant higher diagnostic yield in patients with epilepsy especially in non-DEE patients.

Expectations and knowledge of cannabidiol therapy for childhood epilepsy - A German caregiver survey.

BACKGROUND: Cannabidiol (CBD) has gained popularity among parents of children with epilepsy, even before evidence of efficacy and safety was available. The aim of our survey was to gain information about parental attitude to CBD, as well as expectations and knowledge of CBD for treatment of their child's epilepsy. METHODS: A survey using an open-access online questionnaire for parents or caregivers of children with epilepsy within German-speaking countries from March to June 2019 was used. RESULTS: Of 378 complete questionnaires (mean age of children: 11.1 (standard deviation [SD] 7.4) years), 28% (n = 106) reported previous or current CBD treatment over a mean time of 17.31 months (SD: 19.74), whereas 72% had no personal experience with CBD. Treatment was proposed by parents and not by physicians in 83% of cases and was mainly carried out with prescription-only products (71%, n = 67). Nevertheless, 29% used unregulated, artisanal products. Of all parents with previous experience, n = 77 (73%) reported that they expected CBD to be more efficient than the common antiseizure drugs (ASDs) at the beginning. Forty-five percent reported that their expectations were not met during therapy. Consistently, lack of seizure reduction was the most common reason to discontinue CBD (12/26). Of those responders without CBD experience, 93% would consider CBD for their child. However, the self-reported level of information was considered to be poor or very poor regarding efficacy (76%, n = 177), tolerance (83%, n = 191), interaction with other medication (91%, n = 211), and potential long-term effects (87%, n = 212). CONCLUSIONS: There is a huge interest in CBD but includes potentially unrealistic expectations of its efficacy and tolerance combined with a low level of information. Neuropediatricians should address parents of children with epilepsy regarding potential motivation and expectations of CBD. In addition, parental education, especially on interactions and potential side effects, is strongly recommended.

Haploinsufficiency of KMT2B, Encoding the Lysine-Specific Histone Methyltransferase 2B, Results in Early-Onset Generalized Dystonia.

Early-onset generalized dystonia represents the severest form of dystonia, a hyperkinetic movement disorder defined by involuntary twisting postures. Although frequently transmitted as a single-gene trait, the molecular basis of dystonia remains largely obscure. By whole-exome sequencing a parent-offspring trio in an Austrian kindred affected by non-familial early-onset generalized dystonia, we identified a dominant de novo frameshift mutation, c.6406delC (p.Leu2136Serfs∗17), in KMT2B, encoding a lysine-specific methyltransferase involved in transcriptional regulation via post-translational modification of histones. Whole-exome-sequencing-based exploration of a further 30 German-Austrian individuals with early-onset generalized dystonia uncovered another three deleterious mutations in KMT2B-one de novo nonsense mutation (c.1633C>T [p.Arg545∗]), one de novo essential splice-site mutation (c.7050-2A>G [p.Phe2321Serfs∗93]), and one inherited nonsense mutation (c.2428C>T [p.Gln810∗]) co-segregating with dystonia in a three-generation kindred. Each of the four mutations was predicted to mediate a loss-of-function effect by introducing a premature termination codon. Suggestive of haploinsufficiency, we found significantly decreased total mRNA levels of KMT2B in mutant fibroblasts. The phenotype of individuals with KMT2B loss-of-function mutations was dominated by childhood lower-limb-onset generalized dystonia, and the family harboring c.2428C>T (p.Gln810∗) showed variable expressivity. In most cases, dystonic symptoms were accompanied by heterogeneous non-motor features. Independent support for pathogenicity of the mutations comes from the observation of high rates of dystonic presentations in KMT2B-involving microdeletion syndromes. Our findings thus establish generalized dystonia as the human phenotype associated with haploinsufficiency of KMT2B. Moreover, we provide evidence for a causative role of disordered histone modification, chromatin states, and transcriptional deregulation in dystonia pathogenesis.

SYT1-associated neurodevelopmental disorder: a case series.

Synaptotagmin 1 (SYT1) is a critical mediator of fast, synchronous, calcium-dependent neurotransmitter release and also modulates synaptic vesicle endocytosis. This paper describes 11 patients with de novo heterozygous missense mutations in SYT1. All mutations alter highly conserved residues, and cluster in two regions of the SYT1 C2B domain at positions Met303 (M303K), Asp304 (D304G), Asp366 (D366E), Ile368 (I368T) and Asn371 (N371K). Phenotypic features include infantile hypotonia, congenital ophthalmic abnormalities, childhood-onset hyperkinetic movement disorders, motor stereotypies, and developmental delay varying in severity from moderate to profound. Behavioural characteristics include sleep disturbance and episodic agitation. Absence of epileptic seizures and normal orbitofrontal head circumference are important negative features. Structural MRI is unremarkable but EEG disturbance is universal, characterized by intermittent low frequency high amplitude oscillations. The functional impact of these five de novo SYT1 mutations has been assessed by expressing rat SYT1 protein containing the equivalent human variants in wild-type mouse primary hippocampal cultures. All mutant forms of SYT1 were expressed at levels approximately equal to endogenous wild-type protein, and correctly localized to nerve terminals at rest, except for SYT1M303K, which was expressed at a lower level and failed to localize at nerve terminals. Following stimulation, SYT1I368T and SYT1N371K relocalized to nerve terminals at least as efficiently as wild-type SYT1. However, SYT1D304G and SYT1D366E failed to relocalize to nerve terminals following stimulation, indicative of impairments in endocytic retrieval and trafficking of SYT1. In addition, the presence of SYT1 variants at nerve terminals induced a slowing of exocytic rate following sustained action potential stimulation. The extent of disturbance to synaptic vesicle kinetics is mirrored by the severity of the affected individuals' phenotypes, suggesting that the efficiency of SYT1-mediated neurotransmitter release is critical to cognitive development. In summary, de novo dominant SYT1 missense mutations are associated with a recognizable neurodevelopmental syndrome, and further cases can now be diagnosed based on clinical features, electrophysiological signature and mutation characteristics. Variation in phenotype severity may reflect mutation-specific impact on the diverse physiological functions of SYT1.

Benign epilepsy with centrotemporal spikes: Correlating spike frequency and neuropsychology.

OBJECTIVES: Neuropsychological sequelae are a feature of benign epilepsy with centrotemporal spikes (BECTS) in children. A correlation between the frequency of interictal EEG discharges and the cognitive as well as behavioral profile of the patients has been suspected but not proven. MATERIALS AND METHODS: Children with BECTS that had not yet been treated were included into a randomized controlled trial. In the initial visit, EEGs were recorded. The frequency of interictal discharges was quantified. Correlations between the discharge frequency and the performance in a neuropsychological test battery were examined. RESULTS: The cognitive test results were within or slightly above normal range (Culture-free intelligence test: 99.4%-confidence interval [CI]: [50.3, 59.9], test standardized to a population mean of 50). Parent-reported behavioral abnormalities were statistically significantly increased (CBCL total score CI: [51.9, 61.9], population mean as above). Correlations between the frequency of interictal epileptic discharges and the test results could not be identified (lowest encountered P-value: 0.034, not significant after correction for multiple testing). CONCLUSION: The data do not support the hypothesis that the frequency of the interictal EEG discharges influences the neurocognitive performance or behavioral parameters of children with BECTS.

Neurological Sequelae due to Inborn Metabolic Diseases in Pediatric Refugees: Challenges in Treating the Untreated.

In the 2015 mass migration from Syria and neighboring countries, Germany received an unprecedented number of 4,76,649 asylum applications. As many of the refugees arrived in Southern Germany via the Austrian border, the city of Munich was faced with the majority of Germany's inflow of war refugees and their complex health issues. Among the refugees were a high number of children. Their main health issues were infectious diseases and surgical procedures due to trauma, but we also encountered complex chronic diseases. This report describes clinical history, signs and symptoms, diagnostics, and treatment of six pediatric patients with untreated inborn errors of metabolism (IEM): phenylketonuria, biotinidase deficiency, HMG-CoA lyase deficiency, mucopolysaccharidosis type II, and mucopolysaccharidosis type VI. Since early diagnosis and treatment is essential in IEM, both delayed diagnosis and inadequate therapy in refugee children may lead to significant brain injury, organ damage, and even death. Severe neurological sequelae in both phenylketonuria and HMG-CoA lyase deficiency could have been prevented by newborn screening. Screening programs are necessary to improve the prognoses for refugee children. European Union governments and involved health care systems should pursue early diagnosis and treatment in pediatric refugees regarding IEM to prevent neurological long-term sequelae.

Genetic and neurodevelopmental spectrum of SYNGAP1-associated intellectual disability and epilepsy.

OBJECTIVE: We aimed to delineate the neurodevelopmental spectrum associated with SYNGAP1 mutations and to investigate genotype-phenotype correlations. METHODS: We sequenced the exome or screened the exons of SYNGAP1 in a total of 251 patients with neurodevelopmental disorders. Molecular and clinical data from patients with SYNGAP1 mutations from other centres were also collected, focusing on developmental aspects and the associated epilepsy phenotype. A review of SYNGAP1 mutations published in the literature was also performed. RESULTS: We describe 17 unrelated affected individuals carrying 13 different novel loss-of-function SYNGAP1 mutations. Developmental delay was the first manifestation of SYNGAP1-related encephalopathy; intellectual disability became progressively obvious and was associated with autistic behaviours in eight patients. Hypotonia and unstable gait were frequent associated neurological features. With the exception of one patient who experienced a single seizure, all patients had epilepsy, characterised by falls or head drops due to atonic or myoclonic seizures, (myoclonic) absences and/or eyelid myoclonia. Triggers of seizures were frequent (n=7). Seizures were pharmacoresistant in half of the patients. The severity of the epilepsy did not correlate with the presence of autistic features or with the severity of cognitive impairment. Mutations were distributed throughout the gene, but spared spliced 3' and 5' exons. Seizures in patients with mutations in exons 4-5 were more pharmacoresponsive than in patients with mutations in exons 8-15. CONCLUSIONS: SYNGAP1 encephalopathy is characterised by early neurodevelopmental delay typically preceding the onset of a relatively recognisable epilepsy comprising generalised seizures (absences, myoclonic jerks) and frequent triggers.

Practical Recommendations for Robot-Assisted Treadmill Therapy (Lokomat) in Children with Cerebral Palsy: Indications, Goal Setting, and Clinical Implementation within the WHO-ICF Framework.

Active participation and the highest level of independence during daily living are primary goals in neurorehabilitation. Therefore, standing and walking are key factors in many rehabilitation programs. Despite inconclusive evidence considering the best application and efficacy of robotic tools in the field of pediatric neurorehabilitation, robotic technologies have been implemented to complement conventional therapies in recent years. A group of experienced therapists and physicians joined in an "expert panel." They compared their clinical application protocols, discussed recurring open questions, and developed experience-based recommendations for robot-assisted treadmill therapy (exemplified by the Lokomat, Hocoma, Volketswil, Switzerland) with a focus on children with cerebral palsy. Specific indications and therapeutic goals were defined considering the severity of motor impairments and the International Classification of Functioning, Disability and Health framework (ICF). After five meetings, consensus was found and recommendations for the implementation of robot-assisted treadmill therapy including postsurgery rehabilitation were proposed. This article aims to provide a comprehensive overview on therapeutical applications in a fast developing field of medicine, where scientific evidence is still scarce. These recommendations can help physicians and therapists to plan the child's individual therapy protocol of robot-assisted treadmill therapy.

Patient-specific determinants of responsiveness to robot-enhanced treadmill therapy in children and adolescents with cerebral palsy.

AIM: The aim of the study was to evaluate patient-specific determinants of responsiveness to robot-enhanced repetitive treadmill therapy (ROBERT) in patients with early-developed movement disorders. METHOD: Patients were treated over 12 sessions during a 3-week period. Gross Motor Function Measure-66 (GMFM-66) scores 1 day before ROBERT were compared with scores recorded 1 day after ROBERT. The association of GMFM-66 baseline score, age, sex, aetiology, and add-on botulinum toxin therapy to response to treatment was assessed. RESULTS: Eighty-three patients aged between 4 and 18 years (48 males, 35 females; mean age 10y 8mo, SD 6y 1mo; Gross Motor Function Classification System level I [n=12], II [n=21], III [n=35], IV [n=10], and V [n=1]) were each treated for a total of 7.2 (SD 1.9) treadmill walking hours. Aetiology was bilateral spastic cerebral palsy (BS-CP; n=69), unilateral CP (n=3), ataxic CP (n=3), hereditary spastic paraparesis (n=6), and genetic syndrome including spasticity (n=2). Meaningful improvements were observed in GMFM-66 (+2.5; 95% CI 2.0-3.0), GMFM-D (+5.2; 95% CI 3.6-6.8), and GMFM-E (+4.0; 95% CI 2.8-5.3). There was a high inter-individual variability in treatment response. After multivariable adjustment, the improvements in GMFM-66 and GMFM-E scores were positively associated with the GMFM-66 baseline score. The effect on GMFM-D improvement was inversely associated with age. INTERPRETATION: Gross motor abilities at baseline and age were identified as relevant determinants for the high degree of interpersonal variability in response to ROBERT.

Risk of behavioral disturbances in pediatric patients with epilepsy and mild to moderate cognitive impairment: A cross-sectional study.

OBJECTIVE: The aim of the study was to assess whether children and adolescents with epilepsy are at higher risk of behavioral disturbances when they have concomitant cognitive disturbances. METHODS: Behavioral scores were generated using the Child Behavior Checklist (CBCL). Cognitive evaluation was applied by using different age appropriate versions of the Wechsler Intelligence Scale. CBCL scores (total, externalizing, internalizing) were compared between patients with and without intellectual disability (IQ score < 70 and ≥70, respectively). RESULTS: 144 (10.2 mean age, 6.0-17.9 range) patients were recruited for the study. Patients with mild to moderate intellectual disability (full-scale intelligence quotient (FSIQ) < 70) were not at higher risk of behavioral disturbances (total CBCL score ≥ 63) than patients without cognitive impairment. The mean total CBCL score was 62.0 ± 10.6 (range 42.0-83.5, 95% CI 57.9-62.0) and 59.3 ± 10.3 (range 38.0-80.0, CI 57.4-61.2) for patients with FSIQ < 70 and ≥70, respectively. There was no correlation between FSIQ and total CBCL scores. These findings were true for all IQ subcategories. SIGNIFICANCE: Behavioral disturbances among children and adolescents with epilepsy occur despite the presence or absence of intellectual dysfunction with respect to full-scale IQ.

IQ changes after pediatric epilepsy surgery: a systematic review and meta-analysis.

OBJECTIVE: This systematic review aimed to assess the intellectual outcome of children who underwent surgery for epilepsy. METHODS: A systematic review of electronic databases was conducted on December 3, 2021, for PubMed and January 11, 2022, for Web of Science. The review was conducted according to the PRISMA guidelines. The included studies reported on intelligence quotient (IQ) or developmental quotient (DQ) before and after epilepsy surgery in children. Studies were included, if the patients had medically intractable epilepsy and if the study reported mainly on curative surgical procedures. We conducted a random-effects meta-analysis to determine the mean change of IQ/DQ. RESULTS: Fifty-seven studies reporting on a total of 2593 patients met the inclusion criteria. The mean age at surgery was 9.2 years (± 3.44; range 2.4 months-19.81 years). Thirty-eight studies showed IQ/DQ improvement on a group level, 8 yielded stable IQ/DQ, and 19 showed deterioration. Pooled analysis revealed a significant mean gain in FSIQ of + 2.52 FSIQ points (95% CI 1.12-3.91). The pooled mean difference in DQ was + 1.47 (95% CI - 6.5 to 9.5). The pooled mean difference in IQ/DQ was 0.73 (95% CI - 4.8 to 6.2). Mean FSIQ gain was significantly higher in patients who reached seizure freedom (+ 5.58 ± 8.27) than in patients who did not (+ 0.23 ± 5.65). It was also significantly higher in patients who stopped ASM after surgery (+ 6.37 ± 3.80) than in patients who did not (+ 2.01 ± 2.41). Controlled studies showed a better outcome in the surgery group compared to the non-surgery group. There was no correlation between FSIQ change and age at surgery, epilepsy duration to surgery, and preoperative FSIQ. SIGNIFICANCE: The present review indicates that there is a mean gain in FSIQ and DQ in children with medically intractable epilepsy after surgery. The mean gain of 2.52 FSIQ points reflects more likely sustainability of intellectual function rather than improvement after surgery. Seizure-free and ASM-free patients reach higher FSIQ gains. More research is needed to evaluate individual changes after specific surgery types and their effect on long-term follow-up.