Scn2a

PURPOSE: There are limited psychometric data on outcome measures for children with Developmental Epileptic Encephalopathies (DEEs), beyond measuring seizures, and no data to describe meaningful change. This study aimed to explore parent perceptions of important differences in functional abilities that would guide their participation in clinical trials. METHODS: This was a descriptive qualitative study. Semi-structured one-on-one interviews were conducted with 10 families (15 parent participants) with a child with a SCN2A-DEE [8 male, median (range) age 7...

UNLABELLED: Neuronal hyperexcitability is a hallmark of seizures. It has been recently shown in rodent models of seizures that microglia, the brain's resident immune cells, can respond to and modulate neuronal excitability. However, how human microglia interacts with human neurons to regulate hyperexcitability mediated by epilepsy-causing genetic mutation found in human patients remains unknown. The SCN2A genetic locus is responsible for encoding the voltage-gated sodium channel Nav1...

SCN2A protein-truncating variants (PTV) can result in neurological disorders such as autism spectrum disorder and intellectual disability, but they are less likely to cause epilepsy in comparison to missense variants. While in vitro studies showed PTV reduce action potential firing, consequences at in vivo network level remain elusive. Here, we generated a mouse model of Scn2a insufficiency using antisense oligonucleotides (Scn2a ASO mice), which recapitulated key clinical feature of SCN2A PTV disorders...

Autism spectrum disorder (ASD) is a major neurodevelopmental disorder affecting 1 in 36 children in the United States. While neurons have been the focus to understand ASD, an altered neuro-immune response in the brain may be closely associated with ASD, and a neuro-immune interaction could play a role in the disease progression. As the resident immune cells of the brain, microglia regulate brain development and homeostasis via core functions including phagocytosis of synapses. While ASD has been traditionally considered a polygenic disorder, recent large-scale human genetic studies have identified SCN2A deficiency as a leading monogenic cause of ASD and intellectual disability...

OBJECTIVE: SCN2A gene pathogenic variants are associated with a wide phenotypic spectrum, encompassing epilepsy, developmental delay, and autism spectrum disorder. Researches conducted in Denmark have revealed a disease frequency of approximately 1/78,608 (0.0012%) live births in this population. We estimated the frequency of SCN2A-related disorder in the birth cohort of Brescia and its province between 2002 and 2021. METHODS: Frequency was calculated by ratio between patients with SCN2A pathogenic variant and the total number of live births at the Regional Epilepsy Center of Brescia, between 2002 and 2021...

Numerous pathogenic variants of SCN2A gene, encoding voltage-gated sodium channel α2 subunit Nav1.2 protein, have been identified in a wide spectrum of neuropsychiatric disorders including schizophrenia. However, pathological mechanisms for the schizophrenia-relevant behavioral abnormalities caused by the variants remain poorly understood. Here in this study, we characterized mouse lines with selective Scn2a deletion at schizophrenia-related brain regions, medial prefrontal cortex (mPFC) or ventral tegmental area (VTA), obtained by injecting adeno-associated viruses (AAV) expressing Cre recombinase into homozygous Scn2a-floxed (Scn2afl/fl ) mice, in which expression of the Scn2a was locally deleted in the presence of Cre recombinase...

BACKGROUND: Despite the high consanguinity rates, data on genetic epilepsy in Saudi Arabia is limited. The objective of the current study was to characterize genetic mutations associated with epilepsy in pediatric patients and describe their phenotypic presentations. METHODS: A retrospective chart review was conducted among children presented with epilepsy in one center in Saudi Arabia between 2015 and 2018. Only those who had undergone genetic testing were included...

A range of epilepsies, including the most severe group of developmental and epileptic encephalopathies (DEEs), are caused by gain-of-function variants in voltage-gated channels. Here we report the generation and characterisation of an iPSC cell line from the fibroblasts of a girl with early infantile DEE carrying heterozygous missense gain-of-function mutation (R1882Q) in Nav 1.2(SCN2A) protein, using transient transfection with a single mRNA molecule. The established iPSC line displays typical human primed pluripotent stem cell characteristics: typical colony morphology and robust expression of pluripotency-associated marker genes, ability to give rise to derivatives of all three embryonic germ layers, and normal karyotype without any SNP array-detectable copy number variations...

OBJECTIVE: Literature on the genotypic spectrum of Infantile Epileptic Spasms Syndrome (IESS) in children is scarce from developing countries. This multicentre collaboration evaluated the genotypic and phenotypic landscape of genetic IESS in Indian children. METHODS: Between January 2021 and June 2022, this cross-sectional, study was conducted at six centers in India. Children with genetically confirmed IESS, without definite structural-genetic and structural-metabolic etiology, were recruited and underwent detailed in-person assessment for phenotypic characterisation...

Pathogenic variants in voltage-gated sodium (NaV) channel genes including SCN2A, encoding NaV1.2, are discovered frequently in neurodevelopmental disorders with or without epilepsy. SCN2A is also a high-confidence risk gene for autism spectrum disorder (ASD) and nonsyndromic intellectual disability (ID). Previous work to determine the functional consequences of SCN2A variants yielded a paradigm in which predominantly gain-of-function variants cause neonatal-onset epilepsy, whereas loss-of-function variants are associated with ASD and ID...

IMPORTANCE: Polymicrogyria is the most commonly diagnosed cortical malformation and is associated with neurodevelopmental sequelae including epilepsy, motor abnormalities, and cognitive deficits. Polymicrogyria frequently co-occurs with other brain malformations or as part of syndromic diseases. Past studies of polymicrogyria have defined heterogeneous genetic and nongenetic causes but have explained only a small fraction of cases. OBJECTIVE: To survey germline genetic causes of polymicrogyria in a large cohort and to consider novel polymicrogyria gene associations...

BACKGROUND: Although available literature indicates that the incidence of dementia in the epilepsy population and the risk of seizures in the Alzheimer's disease (AD) population are high, the specific genetic risk factors and the interaction mechanism are unclear, rendering rational genetic interpretation rather challenging. AIMS: Our work aims to identify the common core ion channel genes in epilepsy and AD. METHODS: In this study, we first integrated gene expression omnibus datasets (GSE48350 and GSE6834) on AD and epilepsy to identify differentially expressed genes (DEGs), performing Gene Ontology function and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis of DEGs...

There remains an urgent need for new therapies for treatment-resistant epilepsy. Sodium channel blockers are effective for seizure control in common forms of epilepsy, but loss of sodium channel function underlies some genetic forms of epilepsy. Approaches that provide bidirectional control of sodium channel expression are needed. MicroRNAs (miRNA) are small noncoding RNAs which negatively regulate gene expression. Here we show that genome-wide miRNA screening of hippocampal tissue from a rat epilepsy model, mice treated with the antiseizure medicine cannabidiol, and plasma from patients with treatment-resistant epilepsy, converge on a single target-miR-335-5p...

OBJECTIVE: The α subunit of voltage-gated sodium channels in mammals is encoded by nine different genes, and the mutations in the SCN1A, SCN2A, SCN3A and SCN8A genes highly expressed in the CNS have been associated with epilepsy phenotypes. This study aimed at investigating the frequency of SCN1A gene mutations in DS and GEFS+ spectrum phenotype cases and discussing the molecular results in the context of genotype-phenotype correlation. METHODS: 15 patients diagnosed with DS and 54 patients meeting the GEFS+ spectrum criteria were included in this study...

PURPOSE: Early recognition of seizures in neonates secondary to pathogenic variants in potassium or sodium channel coding genes is crucial, as these seizures are often resistant to commonly used anti-seizure medications but respond well to sodium channel blockers. Recently, a characteristic ictal amplitude-integrated electroencephalogram (aEEG) pattern was described in neonates with KCNQ2-related epilepsy. We report a similar aEEG pattern in seizures caused by SCN2A- and KCNQ3-pathogenic variants, as well as conventional EEG (cEEG) descriptions...

AIM: To explore the relationship between social care-related quality of life (SCrQoL) for caregivers of a child with a developmental and epileptic encephalopathy (DEE; such as SCN2A and Dravet syndrome) and health literacy, illness perceptions, and caregiver activation. METHOD: As part of a larger pre-post pilot study of an information linker service, caregivers completed a baseline questionnaire which included demographics and measures to assess SCrQoL, health literacy, illness perceptions, and caregiver activation...

PURPOSE: In Developmental and Epileptic Encephalopathies (DEEs), identifying the precise genetic factors guides the clinicians to apply the most appropriate treatment for the patient. Due to high locus heterogeneity, WES analysis is a promising approach for the genetic diagnosis of DEE. Therefore, the aim of the present study is to evaluate the utility of WES in the diagnosis and treatment of DEE patients. METHODS: The exome data of 29 DEE patients were filtrated for destructive and missense mutations in 1896 epilepsy-related genes to detect the causative variants and examine the genotype-phenotype correlations...

BACKGROUND: Familial alcohol use disorder (AUD) remains an enigma due to various biological and societal confounds. The present study used two of the most adopted and documented rat models, combining the P/NP lines and HAD/LAD replicated lines, of alcoholism as examined through the lens of whole genomic analyses. METHODS: We used complete genome sequencing of the P/NP lines and previous published sequences of the HAD/LAD replicates to enhance discovery of variants associated with AUDs and to remove confounding with genetic background and random genetic drift...

Pathogenic variants in SCN2A are associated with a range of neurodevelopmental disorders (NDD). Despite being largely monogenic, SCN2A -related NDD show considerable phenotypic variation and complex genotype-phenotype correlations. Genetic modifiers can contribute to variability in disease phenotypes associated with rare driver mutations. Accordingly, different genetic backgrounds across inbred rodent strains have been shown to influence disease-related phenotypes, including those associated with SCN2A -related NDD...

Children diagnosed with autism spectrum disorder (ASD) commonly present with sensory hypersensitivity, or abnormally strong reactions to sensory stimuli. Such hypersensitivity can be overwhelming, causing high levels of distress that contribute markedly to the negative aspects of the disorder. Here, we identify the mechanisms that underlie hypersensitivity in a sensorimotor reflex found to be altered in humans and in mice with loss-of-function in the ASD risk-factor gene SCN2A . The cerebellum-dependent vestibulo-ocular reflex (VOR), which helps maintain one's gaze during movement, was hypersensitized due to deficits in cerebellar synaptic plasticity...