Understanding paralogous epilepsy-associated GABA receptor variants: Clinical implications, mechanisms, and potential pitfalls.

Recent discoveries have revealed that genetic variants in γ-aminobutyric acid type A (GABA) receptor subunits can lead to both gain-of-function (GOF) and loss-of-function (LOF) receptors. GABA receptors, however, have a pseudosymmetrical pentameric assembly, and curiously diverse functional outcomes have been reported for certain homologous variants in paralogous genes (paralogous variants). To investigate this, we assembled a cohort of 11 individuals harboring paralogous M1 proline missense variants in , , and Seven mutations (α1, α1, β2, β3, β3, γ2, and γ2) in α1β2/3γ2 receptors were analyzed using electrophysiological examinations and molecular dynamics simulations.

Effectiveness of sodium channel blockers in treating neonatal seizures due to arterial ischemic stroke.

Objective: Few studies have evaluated the efficacy of antiseizure medications (ASMs) according to the etiology of neonatal acute provoked seizures. We aimed to investigate the response to ASMs in term/near term neonates with acute arterial ischemic stroke (AIS), as well as the type of seizure at presentation and the monitoring approach.

Methods: We retrospectively evaluated neonates from 15 European level IV neonatal intensive care units who presented with seizures due to AIS and were monitored by continuous electroencephalography (cEEG) and/or amplitude-integrated EEG (aEEG) in whom actual recordings, timing, doses, and response to ASMs were available for review.

Elucidating the clinical and genetic spectrum of inositol polyphosphate phosphatase INPP4A-related neurodevelopmental disorder.

Purpose: Biallelic INPP4A variants have recently been associated with severe neurodevelopmental disease in single case reports. Here, we expand and elucidate the clinical-genetic spectrum and provide a pathomechanistic explanation for genotype-phenotype correlations.

Methods: Clinical and genomic investigations of 30 individuals were undertaken alongside molecular and in silico modelling and translation reinitiation studies.

Clinical and genetic delineation of autosomal recessive and dominant ACTL6B-related developmental brain disorders.

Purpose: This study aims to comprehensively delineate the phenotypic spectrum of ACTL6B-related disorders, previously associated with both autosomal recessive and autosomal dominant neurodevelopmental disorders. Molecularly, the role of the nucleolar protein ACTL6B in contributing to the disease has remained unclear.

Methods: We identified 105 affected individuals, including 39 previously reported cases, and systematically analysed detailed clinical and genetic data for all individuals.

Distinct neurodevelopmental and epileptic phenotypes associated with gain- and loss-of-function GABRB2 variants.

Background: Variants in GABRB2, encoding the β2 subunit of the γ-aminobutyric acid type A (GABA) receptor, can result in a diverse range of conditions, ranging from febrile seizures to severe developmental and epileptic encephalopathies. However, the mechanisms underlying the risk of developing milder vs more severe forms of disorder remain unclear. In this study, we conducted a comprehensive genotype-phenotype correlation analysis in a cohort of individuals with GABRB2 variants.

Pathways to epilepsy surgery in children with tuberous sclerosis complex-associated epilepsy.

Background: Previous studies showed the efficacy of epilepsy surgery in carefully selected children with epilepsy associated with tuberous sclerosis complex. However, how this selection is conducted, and the characteristics of the patients brought to surgery are still poorly described. By conducting a multicentric retrospective cohort study covering the practice of the last twenty years, we describe the paths leading to epilepsy surgery in children with epilepsy associated with tuberous sclerosis complex.

Phosphatidylserine enriched with polyunsaturated n-3 fatty acid supplementation for attention-deficit hyperactivity disorder in children and adolescents with epilepsy: A randomized placebo-controlled trial.

Background: Attention-deficit hyperactivity disorder (ADHD) is a frequent comorbidity in children with epilepsy, which management mostly relies on the usual treatments of ADHD, especially methylphenidate. Supplementation with polyunsaturated n-3 Fatty Acid (PUFA) has been proposed as an alternative therapeutic approach in ADHD without epilepsy but has never been evaluated in epilepsy-associated ADHD.

Methods: A multicenter double blind randomized placebo-controlled trial evaluating supplementation with PUFA, in eicosapentaenoic- and docosahexaenoic-acid form, conjugated to a phospholipid vector (PS-Omega3) in children aged >6 and <16-years old, and suffering from any type of epilepsy and ADHD (inattentive or combined type) according to DSM-V.

Diffuse interstitial lung disease in a male fetus with periventricular nodular heterotopia and filamin A mosaic variant.

Background: Most periventricular nodular heterotopias (PNHs) are associated with a mutation in the filamin A (FLNA) gene in Xq28. This condition is associated with cardiovascular malformations, connective tissue abnormalities, epilepsy, and intellectual deficiency of varying severity.

Materials And Methods: We report a new FLNA gene mutation in a male patient associated with PNH and diffuse interstitial lung disease.

Real-life data comparing the efficacy of vigabatrin and oral steroids given sequentially or combined for infantile epileptic spasms syndrome.

Aims: The prognosis of Infantile epileptic spasm syndrome (IESS), relates to the underlying etiology and delay in controlling epileptic spasms. Based on the spasm-free rate, a randomized controlled trial has demonstrated the superiority of combining oral steroids and vigabatrin over oral steroids alone but confirmation in real-life conditions is mandatory.

Methods: We compared two real-life IESS cohorts: a multicenter, retrospective cohort of 40 infants treated with vigabatrin followed by a sequential (ST) addition of steroids, and a prospective, single-center cohort of 58 infants treated with an immediate combination of vigabatrin and steroids (CT).

Parents' experiences of parenting a child with profound intellectual and multiple disabilities in France: A qualitative study.

Introduction: Parents of persons with profound intellectual and multiple disabilities (PIMD) play a major and often lifelong role in the care and support of their child. A better understanding of parents' perspectives regarding their experiences of parenting their child with PIMD is essential to support them more effectively. Although this topic has been explored extensively in Anglo-Saxon and Northern European countries, little is known about the experience of these parents in a highly institutionalized context such as that in France.

Efficacy and tolerance of cannabidiol in the treatment of epilepsy in patients with Rett syndrome.

We aim to assess the efficacy and tolerance of cannabidiol as adjunctive therapy for Rett syndrome (RTT) patients with epilepsy. We conducted a longitudinal observational study through a monocentric cohort of 46 patients with RTT. Patients were recruited from March 2020 to October 2022 and were treated with Epidyolex® (cannabidiol, CBD, 100 mg/mL oral solution).

GluK2 Is a Target for Gene Therapy in Drug-Resistant Temporal Lobe Epilepsy.

Objective: Temporal lobe epilepsy (TLE) is characterized by recurrent seizures generated in the limbic system, particularly in the hippocampus. In TLE, recurrent mossy fiber sprouting from dentate gyrus granule cells (DGCs) crea an aberrant epileptogenic network between DGCs which operates via ectopically expressed GluK2/GluK5-containing kainate receptors (KARs). TLE patients are often resistant to anti-seizure medications and suffer significant comorbidities; hence, there is an urgent need for novel therapies.

Variants in SART3 cause a spliceosomopathy characterised by failure of testis development and neuronal defects.

Squamous cell carcinoma antigen recognized by T cells 3 (SART3) is an RNA-binding protein with numerous biological functions including recycling small nuclear RNAs to the spliceosome. Here, we identify recessive variants in SART3 in nine individuals presenting with intellectual disability, global developmental delay and a subset of brain anomalies, together with gonadal dysgenesis in 46,XY individuals. Knockdown of the Drosophila orthologue of SART3 reveals a conserved role in testicular and neuronal development.

Impact of cardiac surgical timing on the neurodevelopmental outcomes of newborns with Complex congenital heart disease (CHD).

Background: More than half of infants with complex congenital heart disease (CHD) will have a neurodevelopmental disorder of multifactorial causes. The preoperative period represents a time-window during which neonates with complex CHD are in a state of hypoxia and hemodynamic instability, which fosters the emergence of brain injuries and, thus, affects early brain networks and neurodevelopmental outcomes. Currently, there is no consensus regarding the optimal age for cardiac surgery in terms of neurodevelopmental outcomes, and its definition is a real challenge.

Before the first seizure: The developmental imprint of infant epilepsy on neurodevelopment.

In light of the heterogeneity of epilepsy, both from a clinical and from an etiological perspective, it is difficult to establish a link between epilepsy and development that can be generalized to all infantile epilepsies. In general however, early-onset epilepsy has a poor developmental prognosis that is significantly linked to several parameters: age at first seizure, drug resistance, treatment, and etiology. This paper discusses the relationship between visible epilepsy parameters (those that allow the diagnosis of epilepsy) and neurodevelopment in infants, with special focus on Dravet syndrome and KCNQ2-related epilepsy, two common developmental and epileptic encephalopathies; and focal epilepsy caused by focal cortical dysplasia, which often begins during infancy.

Clinical and Neurophysiologic Phenotypes in Neonates With Encephalopathy.

Background And Objectives: encephalopathy is an ultra-rare autosomal recessive neonatal encephalopathy. We delineate the neonatal electroclinical phenotype at presentation and provide insights for early diagnosis.

Methods: Through a multinational collaborative, we studied a cohort of neonates with encephalopathy associated with biallelic pathogenic variants in for whom detailed clinical, neurophysiologic, and neuroimaging information was available from the onset of symptoms.

Overview of therapeutic options for epilepsy.

Tuberous sclerosis (TSC) epilepsy includes infantile spasms and focal seizures before the age of 2 years, whereas focal seizures are predominant over 2 years and generalized seizures may occasionally be part of Lennox-Gastaut syndrome. The better and earlier the seizure control, the better the child's subsequent cognitive and behavioral prognosis. As for epilepsy of other causes, therapeutic options depend on the type of seizure/epilepsy, age and drug resistance, but there are significant specificities for TSC.

Objective Evaluation of Clinical Actionability for Genes Involved in Myopathies: 63 Genes with a Medical Value for Patient Care.

The implementation of high-throughput diagnostic sequencing has led to the generation of large amounts of mutational data, making their interpretation more complex and responsible for long delays. It has been important to prioritize certain analyses, particularly those of "actionable" genes in diagnostic situations, involving specific treatment and/or management. In our project, we carried out an objective assessment of the clinical actionability of genes involved in myopathies, for which only few data obtained methodologically exist to date.

KCNQ2 R144 variants cause neurodevelopmental disability with language impairment and autistic features without neonatal seizures through a gain-of-function mechanism.

Background: Prior studies have revealed remarkable phenotypic heterogeneity in KCNQ2-related disorders, correlated with effects on biophysical features of heterologously expressed channels. Here, we assessed phenotypes and functional properties associated with KCNQ2 missense variants R144W, R144Q, and R144G. We also explored in vitro blockade of channels carrying R144Q mutant subunits by amitriptyline.