Epileptic Encephalopathy in Infants and Children

A Comprehensive Review on Current Insights Into Epileptic Encephalopathy: Pathogenesis and Therapeutic Strategies

Epileptic encephalopathy (EE) represents a challenging group of disorders characterized by severe epilepsy and significant cognitive, behavioral, and neurological impairments. This comprehensive review aims to elucidate the current insights into the pathogenesis and therapeutic strategies for these disorders. Pathogenesis involves a complex interplay of genetic factors, neurobiological mechanisms, and environmental influences that contribute to the severity and progression of symptoms. Clinical manifestations are diverse, encompassing various seizure types, cognitive and behavioral impairments, and developmental delays. Current therapeutic strategies include pharmacological treatments, nonpharmacological interventions, and emerging therapies such as gene and stem cell therapy. Despite advancements, significant challenges and limitations remain, highlighting the need for ongoing research and innovation. This review synthesizes existing knowledge, identifies research gaps, and proposes future directions, emphasizing the potential for personalized medicine to improve patient outcomes and quality of life.

Generation of two patient specific GABRD variants and their isogenic controls for modeling epilepsy

Developmental and epileptic encephalopathies (DEEs) are early-onset conditions that cause intractable seizures and developmental delays. Missense variants in Gamma-aminobutyric acid type A receptor (GABAAR) subunits commonly cause DEEs. Ahring et al. (2022) showed a variant in the gene that encodes the delta subunit (GABRD) is strongly associated with the gain-of-function of extrasynaptic GABAAR. Here, we report the generation of two patient-specific human induced pluripotent stem cells (hiPSC) lines with (i) a de novo variant and (ii) a maternal variant, both for the pathogenic GABRD c.872 C>T, (p.T291I). The variants in the generated cell line were corrected using the CRISPR-Cas9 gene editing technique (respective isogenic control lines).

Randomized placebo-controlled crossover trial of memantine in children with epileptic encephalopathy

Memantine is an N-methyl-D-aspartate receptor antagonist, approved for dementia treatment. There is limited evidence of memantine showing benefit for paediatric neurodevelopmental phenotypes, but no randomized placebo-controlled trials in children with developmental and epileptic encephalopathy. In this randomized double-blind placebo-controlled crossover trial (Trial registration: https://clinicaltrials.gov/ct2/show/NCT03779672), patients with developmental and epileptic encephalopathy received memantine and placebo, each for a 6-week period separated by a 2-week washout phase. Electroencephalography, seizure diary, patient caregivers' global impression, serum inflammatory markers and neuropsychological evaluation were performed at baseline and after each treatment phase. The primary outcome measure was classification as a 'responder', defined as ≥2 of: >50% seizure frequency reduction, electroencephalography improvement, caregiver clinical impression improvement or clear neuropsychological testing improvement. Thirty-one patients (13 females) enrolled. Two patients withdrew prior to initiating medication and two (twins) had to be removed from analysis. Of the remaining 27 patients, nine (33%) were classified as responders to memantine versus two (7%) in the placebo group (P < 0.02). Electroencephalography improvement was seen in eight patients on memantine compared to two on placebo (P < 0.04). Seizure improvement was observed in eight patients on memantine and two on placebo (P < 0.04). Caregivers reported overall clinical improvement in 10 patients on memantine compared to seven on placebo (not significant). Statistical analysis of neuropsychological evaluation suggested improvements in symptoms of attention-deficit hyperactivity disorder and autism. Memantine is a safe and effective treatment for children with developmental and epileptic encephalopathy, having the potential to improve both seizure control and cognitive function.

Characterizing a rare neurogenetic disease, SLC13A5 citrate transporter disorder, utilizing clinical data in a cloud-based medical record collection system

Introduction: SLC13A5 citrate transporter disorder is a rare autosomal recessive genetic disease that has a constellation of neurologic symptoms. To better characterize the neurologic and clinical laboratory phenotype, we utilized patient medical records collected by Ciitizen, an Invitae company, with support from the TESS Research Foundation. Methods: Medical records for 15 patients with a suspected genetic and clinical diagnosis of SLC13A5 citrate transporter disorder were collected by Ciitizen, an Invitae company. Genotype, clinical phenotypes, and laboratory data were extracted and analyzed. Results: The 15 patients reported all had epilepsy and global developmental delay. Patients continued to attain motor milestones, though much later than their typically developing peers. Clinical diagnoses support abnormalities in communication, and low or mixed tone with several movement disorders, including, ataxia and dystonia. Serum citrate was elevated in the 3 patients in whom it was measured; other routine laboratory studies assessing renal, liver and blood function had normal values or no consistent abnormalities. Many electroencephalograms (EEGs) were performed (1 to 35 per patient), and most but not all were abnormal, with slowing and/or epileptiform activity. Fourteen of the patients had one or more brain magnetic resonance imaging (MRI) reports: 7 patients had at least one normal brain MRI, but not with any consistent findings except white matter signal changes. Discussion: These results show that in addition to the epilepsy phenotype, SLC13A5 citrate transporter disorder impacts global development, with marked abnormalities in motor abilities, tone, coordination, and communication skills. Further, utilizing cloud-based medical records allows industry, academic, and patient advocacy group collaboration to provide preliminary characterization of a rare genetic disorder. Additional characterization of the neurologic phenotype will be critical to future study and developing treatment for this and related rare genetic disorders.

Epilepsy and Cognitive Impairment in Childhood and Adolescence: A Mini-Review

Managing epilepsy in people with an intellectual disability remains a therapeutic challenge and must take into account additional issues such as diagnostic difficulties and frequent drug resistance. Advances in genomic technologies improved our understanding of epilepsy and raised the possibility to develop patients-tailored treatments acting on the key molecular mechanisms involved in the development of the disease. In addition to conventional antiseizure medications (ASMs), ketogenic diet, hormone therapy and epilepsy surgery play an important role, especially in cases of drugresistance. This review aims to provide a comprehensive overview of the mainfactors influencing cognition in children and adolescents with epilepsy and the main therapeutic options available for the epilepsies associated with intellectual disability.

Efficacy of pulse intravenous methylprednisolone in epileptic encephalopathy: a randomised controlled trial

BACKGROUND

High-level evidence for using steroids in epileptic encephalopathy (EE), other than West syndrome (WS), is lacking. This study investigated the efficacy and safety of pulse intravenous methylprednisolone (IVMP) in EE other than WS.

METHODS

This is an open-label evaluator-blinded randomised controlled study. Children aged 6 months or more with EE other than WS were included. Eighty children were randomised into intervention and non-intervention groups with 40 in each group. At the first visit (T1) seizure frequency, electroencephalographic (EEG) and Vineland Social Maturity Scale (VSMS) were obtained, and antiseizure medication (ASM) were optimised. After 1 month (T2), subjects were randomised to intervention (ASM+3 months IVMP pulse) or non-intervention group (only ASM) with 40 subjects in each group. They were followed up for 4 months (T3) and assessed.

RESULTS

After 4 months of follow-up, 75% of patients receiving IVMP had >50% seizure reduction versus 15.4% in control group (χ2=28.29, p<0.001) (RR 4.88, 95% CI 2.29 to 10.40), median percentage change in seizure frequency (91.41% vs 10%, p<0.001), improvement in EEG (45.5% vs 9.4%, χ2=10.866, p=0.001) and social age domain of VSMS scores (Z=-3.62, p<0.001) compared with baseline. None of the patients in the intervention group had any serious side-effects.

DISCUSSION

Three-month pulse IVMP therapy showed significant improvement in seizure frequency, EEG parameters and VSMS scores, with no steroid-related serious adverse effects. It can be considered as a safe and effective add on treatment in children with EE other than WS.

TRIAL REGISTRATION NUMBER

CTRI/2019/02/017807.

Use of Zebrafish Models to Boost Research in Rare Genetic Diseases

Rare genetic diseases are a group of pathologies with often unmet clinical needs. Even if rare by a single genetic disease (from 1/2000 to 1/more than 1,000,000), the total number of patients concerned account for approximatively 400 million peoples worldwide. Finding treatments remains challenging due to the complexity of these diseases, the small number of patients and the challenge in conducting clinical trials. Therefore, innovative preclinical research strategies are required. The zebrafish has emerged as a powerful animal model for investigating rare diseases. Zebrafish combines conserved vertebrate characteristics with high rate of breeding, limited housing requirements and low costs. More than 84% of human genes responsible for diseases present an orthologue, suggesting that the majority of genetic diseases could be modelized in zebrafish. In this review, we emphasize the unique advantages of zebrafish models over other in vivo models, particularly underlining the high throughput phenotypic capacity for therapeutic screening. We briefly introduce how the generation of zebrafish transgenic lines by gene-modulating technologies can be used to model rare genetic diseases. Then, we describe how zebrafish could be phenotyped using state-of-the-art technologies. Two prototypic examples of rare diseases illustrate how zebrafish models could play a critical role in deciphering the underlying mechanisms of rare genetic diseases and their use to identify innovative therapeutic solutions.

Gene and Phenotype Expansion of Unexplained Early Infantile Epileptic Encephalopathy

Objective: The genetic aetiology of epileptic encephalopathy (EE) is growing rapidly based on next generation sequencing (NGS) results. In this single-centre study, we aimed to investigate a cohort of Chinese children with early infantile epileptic encephalopathy (EIEE). Methods: NGS was performed on 50 children with unexplained EIEE. The clinical profiles of children with pathogenic variants were characterised and analysed in detail. Conservation analysis and homology modelling were performed to predict the impact of STXBP1 variant on the protein structure. Results: Pathogenic variants were identified in 17 (34%) of 50 children. Sixteen variants including STXBP1 (n = 2), CDKL5 (n = 2), PAFAH1B1, SCN1A (n = 9), SCN2A, and KCNQ2 were de novo, and one (PIGN) was a compound heterozygous variant. The phenotypes of the identified genes were broadened. PIGN phenotypic spectrum may include EIEE. The STXBP1 variants were predicted to affect protein stability. Significance: NGS is a useful diagnostic tool for EIEE and contributes to expanding the EIEE-associated genotypes. Early diagnosis may lead to precise therapeutic interventions and can improve the developmental outcome.

Genetic factors and the risk of drug-resistant epilepsy in young children with epilepsy and neurodevelopment disability: A prospective study and updated meta-analysis

Drug-resistant epilepsy (DRE) affects 7% to 20% of children with epilepsy. Although some risk factors for DRE have been identified, the results have not been consistent. Moreover, data regarding the risk factors for epilepsy and its seizure outcome in the first 2 years of life are limited.We analyzed data for children aged 0 to 2 years with epilepsy and neurodevelopmental disability from January, 2013, through December, 2017. These patients were followed up to compare the risk of DRE in patients with genetic defect (genetic group) with that without genetic defect (nongenetic group). Additionally, we conducted a meta-analysis to identify the pooled prevalence of genetic factors in children with DRE.A total of 96 patients were enrolled. A total of 68 patients were enrolled in the nongenetic group, whereas 28 patients were enrolled in the genetic group. The overall DRE risk in the genetic group was 6.5 times (95% confidence interval [CI], 2.15-19.6; p = 0.03) higher than that in the nongenetic group. Separately, a total of 1308 DRE patients were participated in the meta-analysis. The pooled prevalence of these patients with genetic factors was 22.8% (95% CI 17.4-29.3).The genetic defect plays a crucial role in the development of DRE in younger children with epilepsy and neurodevelopmental disability. The results can serve as a reference for further studies of epilepsy panel design and may also assist in the development of improved treatments and prevention strategies for DRE.

Clinical profile and treatment outcome of epilepsy syndromes in children: A hospital-based study in Eastern Nepal

Objective

It is often difficult to diagnose epilepsy syndromes in resource-limited settings. This study was aimed to investigate the prospect of ascertaining the diagnosis, clinical profile, and treatment outcomes of epilepsy syndromes (ESs) among children in a resource-limited setting.

Methods

This was a descriptive study done from 01/07/2009 to 15/06/2017 among children (1-17 years of age) with unprovoked seizures presenting to the pediatric neurology clinic of a university hospital in eastern Nepal. Diagnosis, classification, and treatment of seizures were based upon International League Against Epilepsy guidelines.

Results

Of 768 children with unprovoked seizures, 120 (15.6%) were diagnosed as ES. The age of onset of seizure was unique for each ES. Developmental delay and cerebral palsy were present in 47.5% and 28.3% children, respectively. Common ESs were West syndrome (WS)-26.7%, generalized tonic-clonic seizures alone (GTCSA)-21.7%, self-limited childhood epilepsy with centrotemporal spikes (SLCECTS)-12.5%, childhood absence epilepsy (CAE)-10.0%, Lennox-Gastaut syndrome (LGS)-10.0%, other developmental and epileptic encephalopathies (DEE)-5.8%, self-limited familial infantile epilepsy (SLFIE)-4.2%, and juvenile myoclonic epilepsy (JME)-3.3%. Among children with known outcomes (87/120), overall response to pharmacotherapy and to monotherapy was observed in 72.4% (63/87) and 57.5% (50/87) children, respectively. All children with GTCSA, SLFIE, genetic epilepsy with febrile seizure plus (GEFS+), CAE, SLCECTS, and JME responded to pharmacotherapy and they had normal computerized tomography scans of the brain. Seizures were largely pharmaco-resistant in progressive myoclonus epilepsy (PME)-100.0%, LGS-73.0%, WS-52.0%, and other DEEs-40%.

Significance

A reasonable proportion (15.6%) of unprovoked seizures could be classified into specific ES despite limited diagnostic resources. WS was the most common ES. GTCSA, SLCECTS, CAE, and LGS were other common ESs. GTCSA, SLFIE, CAE, SLCECTS, GEFS+, and JME were largely pharmaco-responsive. PME, WS, and LGS were relatively pharmaco-resistant. Electro-clinical diagnosis of certain ES avoids the necessity of neuroimaging.

Congenital Disorders of Glycosylation from a Neurological Perspective

Most plasma proteins, cell membrane proteins and other proteins are glycoproteins with sugar chains attached to the polypeptide-glycans. Glycosylation is the main element of the post-translational transformation of most human proteins. Since glycosylation processes are necessary for many different biological processes, patients present a diverse spectrum of phenotypes and severity of symptoms. The most frequently observed neurological symptoms in congenital disorders of glycosylation (CDG) are: epilepsy, intellectual disability, myopathies, neuropathies and stroke-like episodes. Epilepsy is seen in many CDG subtypes and particularly present in the case of mutations in the following genes: ALG13, DOLK, DPAGT1, SLC35A2, ST3GAL3, PIGA, PIGW, ST3GAL5. On brain neuroimaging, atrophic changes of the cerebellum and cerebrum are frequently seen. Brain malformations particularly in the group of dystroglycanopathies are reported. Despite the growing number of CDG patients in the world and often neurological symptoms dominating in the clinical picture, the number of performed screening tests eg transferrin isoforms is systematically decreasing as broadened genetic testing is recently more favored. The aim of the review is the summary of selected neurological symptoms in CDG described in the literature in one paper. It is especially important for pediatric neurologists not experienced in the field of metabolic medicine. It may help to facilitate the diagnosis of this expanding group of disorders. Biochemically, this paper focuses on protein glycosylation abnormalities.

Seizing the moment: Zebrafish epilepsy models

Zebrafish are now widely accepted as a valuable animal model for a number of different central nervous system (CNS) diseases. They are suitable both for elucidating the origin of these disorders and the sequence of events culminating in their onset, and for use as a high-throughput in vivo drug screening platform. The availability of powerful and effective techniques for genome manipulation allows the rapid modelling of different genetic epilepsies and of conditions with seizures as a core symptom. With this review, we seek to summarize the current knowledge about existing epilepsy/seizures models in zebrafish (both pharmacological and genetic) and compare them with equivalent rodent and human studies. New findings obtained from the zebrafish models are highlighted. We believe that this comprehensive review will highlight the value of zebrafish as a model for investigating different aspects of epilepsy and will help researchers to use these models to their full extent.

Prognostic factors in epileptic encephalopathies at onset in the first 2 years of life: The experience of a tertiary healthcare center in Italy

INTRODUCTION

The aim of this retrospective cohort study was to identify some prognostic factors in anamnestic/clinical/instrumental data at the onset of epileptic encephalopathy (EE), for multiple outcome measures.

METHODS

We recruited patients diagnosed as affected by EE at Sant'Anna University Hospital, with onset in the first 24 months of life, with follow-up lasting longer than 3 years.

RESULTS

At the end of the follow-up, 6 patients (14%) died within 2 years of age; 20 patient (49%) had a drug-resistant epilepsy (DRE); 9 patients (22%) had a language development delay (LDD); 12 patients (30%) had an autism spectrum disorder (ASD); 20 patients (49%) had a global psychomotor impairment (GPI); 9 patients (22%) needed palliative care; and nobody had a normal psychomotor development. Preexisting developmental delay predicts death (p = 0.009), and in survivors, it is associated with a GPI (p < 0.001); patients with normal neurological examination at the onset of EE only develop a LDD (p = 0.020). Neuroimaging structural alterations are associated with DRE (p = 0.012) and with a GPI (p = 0.013). The history of perinatal risk factors predicts the worst prognosis (death: p = 0.035, GPI: p = 0.015, and access to palliative care: p = 0.007). The absence of early response to treatment is correlated to a poor long-term prognosis (GPI, p = 0.019; DRE, p = 0.001). The multivariate analysis confirms that a normal development at onset predicts the most favorable prognosis, both in terms of survival and cognitive outcome (OR [odds ratio] = 0.1). An early response to treatment is a protective factor for DRE (OR = 0.1). A perinatal pathology is confirmed as an independent prognostic factor of severe comorbidities (access to palliative care: OR = 10.4).

SIGNIFICANCE

This study was conducted to recognize possible prognostic factors among onset data of patients with EE, considering multiple outcome measures. This study design represents an innovative element compared to available papers, which were centered on isolated endpoints of prognosis, such as the prediction of neurocognitive development impairment or drug resistance. The data obtained from the study confirm that EEs prognosis is generally, but not universally, poor. Structural etiology and/or lack of response to antiepileptic drug (AED) within three months are main risk factors for DRE. Normal development at the onset of EEs and early response to treatment are the main positive prognostic factors.

The landscape of early infantile epileptic encephalopathy in a consanguineous population

PURPOSE

Epileptic encephalopathies (EE), are a group of age-related disorders characterized by intractable seizures and electroencephalogram (EEG) abnormalities that may result in cognitive and motor delay. Early infantile epileptic encephalopathies (EIEE) manifest in the first year of life. EIEE are highly heterogeneous genetically but a genetic etiology is only identified in half of the cases, typically in the form of de novo dominant mutations.

METHOD

This is a descriptive retrospective study of a consecutive series of patients diagnosed with EIEE from the participating hospitals. A chart review was performed for all patients. The diagnosis of epileptic encephalopathy was confirmed by molecular investigations in commercial labs. In silico study was done for all novel mutations. A systematic search was done for all the types of EIEE and their correlated genes in the literature using the Online Mendelian Inheritance In Man and PubMed databases.

RESULTS

In this case series, we report 72 molecularly characterized EIEE from a highly consanguineous population, and review their clinical course. We identified 50 variants, 26 of which are novel, causing 26 different types of EIEE. Unlike outbred populations, autosomal recessive EIEE accounted for half the cases. The phenotypes ranged from self-limiting and drug-responsive to severe refractory seizures or even death.

CONCLUSIONS

We reported the largest EIEE case series in the region with confirmed molecular testing and detailed clinical phenotyping. The number autosomal recessive predominance could be explained by the society's high consanguinity. We reviewed all the EIEE registered causative genes in the literature and proposed a functional classification.