Clinical phenotypes of developmental and epileptic encephalopathy-related recurrent KCNH5 missense variant p.R327H in Chinese children.

KCNH5 gene encodes for the voltage-gated potassium channel protein Kv10.2. Here, we investigated the clinical features of developmental and epileptic encephalopathy (DEE) in five Chinese pediatric patients with a missense mutation (p.R327H) in KCNH5 gene. These patients had undergone video EEG to evaluate background features and epileptiform activity, as well as 3.0 T MRI scans for structural analysis and intelligence assessments using the Gesell Developmental Observation or Wechsler Intelligence Scale for Children. Seizure onset occurs between 4 and 10 months of age, with focal and generalized tonic-clonic seizures being common. Initial EEG findings showed multiple multifocal sharp waves, sharp slow waves or spike slow waves, and spike waves. Brain MRI revealed widened extracerebral space in only one patient. Mechanistically, the KCNH5 mutation disrupts the two hydrogen bonds between Arg327 and Asp304 residues, potentially altering the protein's structural stability and function. Almost 80 % of patients receiving add-on valproic acid (VPA) therapy experienced a reduction in epileptic seizure frequency. Altogether, this study presents the first Chinese cohort of pediatric DEE patients with the KCNH5 p.R327H mutation, highlighting focal seizures as the predominant seizure type and incomplete mutation penetrance. Add-on VPA therapy was likely effective in the early stages of DEE pathogenesis.

Corrigendum: Comparison of the effectiveness and safety of perampanel and oxcarbazepine as monotherapy in children and adolescents with newly diagnosed focal epilepsy.

[This corrects the article DOI: 10.3389/fphar.2023.1189058.].

Comparison of the effectiveness and safety of perampanel and oxcarbazepine as monotherapy in children and adolescents with newly diagnosed focal epilepsy.

Objective: This study aims to compare the effectiveness and safety of perampanel and oxcarbazepine as monotherapy in children with focal epilepsy (FE). Methods: This is an ambispective, single-center, non-inferiority study comparing the effectiveness and safety of perampanel (PER) monotherapy and oxcarbazepine (OXC) monotherapy in children with newly diagnosed FE. The primary endpoint was a six-month seizure freedom rate. The secondary endpoints included retention, responder, and seizure freedom rates at 3, 6, and 12 months, respectively. Adverse events (AEs) were also recorded for both groups. Results: One hundred and thirty children and adolescents aged from 4 to 18years newly diagnosed with FE between May 2020 and November 2022 in Wuhan Children's Hospital were included. There were 71 patients in the PER group and 59 patients in the OXC group. In the per protocol set (PPS), 50 (78.1%) in the PER group and 43 (78.2%) in the OXC group completed six months of treatment without seizures. The lower 95% CI (66.0%-87.5%) limit of PER was higher than the non-inferiority margin of 62.4% (80% of the 6-month seizure freedom rate in the OXC group); PER was non-inferior to OXC. The 3-month and 12-month seizure freedom rates were 77.1% and 82.9% for the PER group, respectively, while they were 80.4% and 75.8% for the OXC group. There were no serious adverse events in both groups. Conclusion: PER showed comparable effectiveness and safety compared with OXC in children with newly diagnosed focal epilepsy, which might be an effective and safe treatment for children and adolescents with newly diagnosed FE. Clinical Trial Registration: Identifier ChiCTR2300074696.

Possible Role of Mitochondrial Transfer RNA Gene 5816 A > G Genetic Polymorphism (m.5816A > G) in a 3-Year-Old Child with Dystonia: Report of a Case.

Background Mutations in the mitochondrial transfer RNA (mt-tRNA) gene are a hotspot for mitochondrial DNA (mtDNA) mutations and are most common in mitochondrial diseases. Methods We identified the mt-tRNA gene 5816 A > G (m.5816 A > G) mutation in a 3-year-old child with dystonia who died. We performed clinical evaluation, genetic analysis, and biochemical investigation with mitochondrial function testing. Results Our patient was found to have dystonia with hyperlactatemia. Electroencephalogram findings were abnormal in children with numerous multifocal spikes, multispike, spikes and slow waves, slow waves and low amplitude fast waves, more pronounced in the occipital region bilaterally, and occurring continuously during sleep. One year later, the preexisting patient had seizures lasting 1 to 2 hours and subsequently died. mtDNA sequencing revealed that the proband, her mother, and her grandmother all carried the m.5816A > G mutation. Oxygen consumption rate (OCR) assays revealed that the proband's basal resting OCR, adenosine triphosphate production, proton leak, maximal respiration, and spare capacity OCR were all significantly lower compared with healthy children of the same age. Conclusion The present case demonstrates a childhood dystonia caused by a mt-tRNA gene 5816 A > G mutation, which has never been reported before. Our findings provide valuable new insights into the pathogenic mechanism and function of the m.5816A > G mutation.

Emerging evidence of genotype-phenotype associations of developmental and epileptic encephalopathy due to KCNC2 mutation: Identification of novel R405G.

Developmental and epileptic encephalopathies (DEEs) have high genetic heterogeneity, and DEE due to the potassium voltage-gated channel subfamily C member 2 (KCNC2) variant remains poorly understood, given the scarcity of related case studies. We report on two unrelated Chinese patients, an 11-year-old boy and a 5-year-old girl, diagnosed with global developmental delay (GDD), intellectual disability (ID), and focal impaired awareness seizure characterized by generalized spike and wave complexes on electroencephalogram (EEG) in the absence of significant brain lesions. Whole-exome sequencing (WES) and electrophysiological analysis were performed to detect genetic variants and evaluate functional changes of the mutant KCNC2, respectively. Importantly, we identified a novel gain-of-function KCNC2 variant, R405G, in both patients. Previously reported variants, V471L, R351K, T437A, and T437N, and novel R405G were found in multiple unrelated patients with DEE, showing consistent genotype-phenotype associations. These findings emphasize that the KCNC2 gene is causative for DEE and facilitates treatment and prognosis in patients with DEE due to KCNC2 mutations.

Phenotypic Spectrum and Prognosis of Epilepsy Patients With GABRG2 Variants.

Objective: This study aimed to obtain a comprehensive understanding of the genetic and phenotypic aspects of GABRG2-related epilepsy and its prognosis and to explore the potential prospects for personalized medicine. Methods: Through a multicenter collaboration in China, we analyzed the genotype-phenotype correlation and antiseizure medication (ASM) of patients with GABRG2-related epilepsy. The three-dimensional protein structure of the GABRG2 variant was modeled to predict the effect of GABRG2 missense variants using PyMOL 2.3 software. Results: In 35 patients with GABRG2 variants, 22 variants were de novo, and 18 variants were novel. The seizure onset age was ranged from 2 days after birth to 34 months (median age: 9 months). The seizure onset age was less than 1 year old in 22 patients (22/35, 62.9%). Seizure types included focal seizures (68.6%), generalized tonic-clonic seizures (60%), myoclonic seizures (14.3%), and absence seizures (11.4%). Other clinical features included fever-sensitive seizures (91.4%), cluster seizures (57.1%), and developmental delay (45.7%). Neuroimaging was abnormal in 2 patients, including dysplasia of the frontotemporal cortex and delayed myelination of white matter. Twelve patients were diagnosed with febrile seizures plus, eleven with epilepsy and developmental delay, two with Dravet syndrome, two with developmental and epileptic encephalopathy, two with focal epilepsy, two with febrile seizures, and four with unclassified epilepsy. The proportions of patients with missense variants in the extracellular region and the transmembrane region exhibiting developmental delay were 40% and 63.2%, respectively. The last follow-up age ranged from 11 months to 17 years. Seizures were controlled in 71.4% of patients, and 92% of their seizures were controlled by valproate and/or levetiracetam. Conclusion: The clinical features of GABRG2-related epilepsy included seizure onset, usually in infancy, and seizures were fever-sensitive. More than half of the patients had cluster seizures. Phenotypes of GABRG2-related epilepsy were ranged from mild febrile seizures to severe epileptic encephalopathies. Most patients with GABRG2 variants who experienced seizures had a good prognosis. Valproate and levetiracetam were effective treatments for most patients.

GABRB3-related epilepsy: novel variants, clinical features and therapeutic implications.

OBJECTIVE: This study aimed to comprehensively examine the genetic and phenotypic aspects of GABRB3-related epilepsy and to explore the potential prospects of personalized medicine. METHODS: Genetic testing was conducted in all epilepsy patients without acquired factors for epilepsy. Through the collaboration of multicenter in China, we analyzed the genotype-phenotype correlation and antiepileptic therapy of 26 patients with GABRB3-related epilepsy. RESULTS: Thirteen GABRB3 variants were novel, and 25 were de novo. The seizure onset age ranged from 1 to 21 months (median age 3.75 months). Seizure types predominated including focal seizures (92.3%), generalized tonic-clonic seizures (23.1%), and epileptic spasms (15.4%). Clinical features included cluster seizures (80.8%), fever sensitivity (53.8%), and developmental delay (96.2%). Neuroimaging was abnormal in 10 patients, including dysplasia of the cerebral cortex, dysplasia of the frontal and temporal cortex, delayed myelination, and corpus callosum dysplasia. Eleven patients were diagnosed with developmental and epileptic encephalopathy (DEE), four with West syndrome, three with epilepsy of infancy with migrating focal seizures (EIMFS), one with epilepsy with myoclonic-atonic seizures (EMAS), one with Dravet syndrome, and one with febrile seizures plus (FS+). Seizures were controlled in 57.7% of patients by valproate, levetiracetam, or perampanel in the majority. CONCLUSIONS: The clinical features of GABRB3-related epilepsy included seizure onset in early infancy, cluster seizures and fever sensitivity. Most patients manifest severe epilepsy phenotypes. Valproate, levetiracetam and perampanel seem to have positive effects on seizure control for patients with GABRB3 variants.

Generation of an induced pluripotent stem cell line ATCi001-A from a three-year-old Chinese girl with Brown-Vialetto-Van Laere syndrome-2.

Brown-Vialetto-Van Laere syndrome-2 is a rare neurological disorder characterized by sensory neuronopathy and pontobulbar palsy, caused by variations in SLC52A2 and SLC52A3 genes, encoding the riboflavin transporters. By reprogramming with SOX2, KLF4, c-MYC and OCT3/4, we generated an iPSC cell line from peripheral blood mononuclear cells (PBMCs) collected from a three-year-old Chinese female individual to be used as a disease model. By fully examination, the resulting iPSCs expressed pluripotency-associated stem cell markers, maintained the normal karyotype and proliferative potential for three-germ layer differentiation.

Detection of Disease-Causing SNVs/Indels and CNVs in Single Test Based on Whole Exome Sequencing: A Retrospective Case Study in Epileptic Encephalopathies.

Background: Epileptic encephalopathies (EEs) are a pediatric entity with highly phenotypic and genetic heterogeneity. Both single nucleotide variants (SNVs)/Indels and copy number variations (CNVs) could be the causes. Whole exome sequencing (WES) is widely applied to detect SNVs/Indels, but the bioinformatics approach for detecting CNVs is still limited and weak. In the current study, the possibility of profiling both disease-causing SNVs/Indels and CNVs in a single test based on WES in EEs was evaluated. Methods: The infants diagnosed with EEs were enrolled from a single pediatric epilepsy center between January 2018 and February 2020. Demographic and clinical data were collected. In WES data, the pathogenic SNVs were identified through an in-house pipeline, and pathogenic CNVs were identified by CNVkit. The diagnostic rate was evaluated, and the molecular findings were characterized. Results: A total of 73 infants were included; 36 (49.32%) of them were males. The median age was 7 months. Thirty-two (43.84%) infants had been diagnosed with epilepsy syndrome. The most common type of syndrome was West syndrome (22/73, 30.1%), followed by Dravet syndrome (20/77, 27.4%). Fifty-four (73.97%) had intellectual development delay. The genetic cause of EEs, pathogenic or likely pathogenic variants, were successfully discovered in 46.6% (34/73) of the infants, and 29 (39.7%) infants carried SNVs/Indels, while 5 (6.8%) carried CNVs. The majority of the disease-causing variants were inherited in de novo pattern (25, 71.4%). In addition to showing that the variants in the ion channel encoding genes accounted for the main etiology, we discovered and confirmed two new disease-causing genes, CACNA1E and WDR26. Five discovered CNVs were deletions of 2q24.3, 1p36, 15q11-q13, 16p11.2, and 17p13.3, and all were confirmed by array comparative genomic hybridization. Conclusion: The application of both SNVs/Indels and CNVs detection in a single test based on WES yielded a high diagnosis rate in EEs. WES may serve as a first-tier test with cost-effective benefit in EEs.

Child-Onset Cerebellar Ataxia Caused by Two Compound Heterozygous Variants in ADPRS Gene: A Case Report.

Background: Gene variants of ADP-ribosylserine hydrosylase, also known as ADP-ribosylhydrolase-like 2 (ADPRS or ADPRLH2; OMIM: 610624), can cause stress-induced childhood-onset neurodegeneration with variable ataxia and seizures (CONDSIAS, OMIM: 618170), an ultra-rare neurodegenerative autosomal recessive disorder. ADPRS encodes ADP-ribosylhydrolase 3, which removes poly(ADP-ribose) polymers, whose posttranslational addition occurs under stressful conditions. Case Presentation: After a respiratory tract infection, a 30-month-old male patient presented with unsteady gait that rendered walking impossible without external help. Neurological examination revealed acute cerebellar ataxia, electroencephalogram results were abnormal, and brain magnetic resonance imaging revealed slightly widened cerebellar sulci. Laboratory tests showed decreased levels of thyroid-stimulating hormone, and increased levels of plasma lactic acid and serum cardiac enzymes. The cerebrospinal fluid glucose test was positive. Four months after onset, the patient died of sudden convulsions. Using whole exome sequencing, we identified two novel compound heterozygous ADPRS variants: NM_017825.3:c.580C>T (p.Gln194Ter) and NM_017825.3:c.803-1G>A. RNA sequencing indicated that the former mutation might cause nonsense-mediated mRNA decay. The c.803-1G>A variant was found to be a splice-site mutation that leads to the transcriptional retention of intron 5. According to the guidelines of the American College of Medical Genetics and Genomics, the two variants were classified as pathogenic. Conclusion: We present the first report of the existence of two compound heterozygous variants of ADPRS, which leads to CONDSIAS.

Children Infected With SARS-CoV-2 From Family Clusters.

Background: The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is ongoing globally. Limited data are available for children with SARS-CoV-2 infection. Methods: A retrospective case study was conducted in one designated hospital for children with SARS-CoV-2 infection in Wuhan. Results: Out of the 74 children with laboratory-confirmed SARS-CoV-2 infection, the median age was 5.8 years, with no notable variation based on gender. All of the children had had direct exposure to at least one family member with confirmed SARS-CoV-2 infection. The most common symptoms were cough in 41 (55.4%) and fever in 38 (51.4%). Typical CT patterns of viral pneumonia were exhibited in 40 (54.1%) children, including ground-glass opacity and interstitial abnormalities. However, 17 (23.0%) children were classified as asymptomatic carriers, with neither symptoms nor radiological findings. Also, 68 (91.9%) children recovered fully and showed negative results on RT-PCR assay by nasopharyngeal swabs during our observation period. In contrast to the negative result for nasopharyngeal swab, 34% of the anal swabs showed a continued positive result. The mean hospitalization days of the children discharged after full recovery was 10.0 days. Conclusion: Within family clusters that had SARS-CoV-2 infection, children had mild or even asymptomatic illness. Although CT is highly sensitive, it should be avoided in follow-up of the disease in consideration of the radiological hazards and limited clinical benefits for mild illness in children. Furthermore, it is advocated that both nasopharyngeal and anal swabs should be confirmed negative for viral load prior to declaring full recovery so as to avoid oral-fecal transmission. Asymptomatic children with family clusters are potentially a little-known source of COVID-19. This therefore warrants an urgent reassessment of the transmission dynamics of the current outbreak.

Children Hospitalized With Severe COVID-19 in Wuhan.

BACKGROUND: Novel coronavirus disease (COVID-19) is spreading globally. Little is known about the risk factors for the clinical outcomes of COVID-19 in children. METHODS: A retrospective case-control study was taken in children with severe acute respiratory syndrome coronary virus-2 infection in Wuhan Children's Hospital. Risk factors associated with the development of COVID-19 and progression were collected and analyzed. RESULTS: Eight of 260 children diagnosed with severe COVID-19 pneumonia were included in the study. Thirty-five children with COVID-19 infection matched for age, sex and date of admission, and who classified as non-severe type, were randomly selected from the hospital admissions. For cases with severe pneumonia caused by COVID-19, the most common symptoms were dyspnea (87.5%), fever (62.5%) and cough (62.5%). In laboratory, white blood cells count was significantly higher in severe children than non-severe children. Levels of inflammation bio-makers such as hsCRP, IL-6, IL-10 and D-dimer elevated in severe children compared with non-severe children on admission. The level of total bilirubin and uric acid clearly elevated in severe children compared with non-severe children on admission. All of severe children displayed the lesions on chest CT, more lung segments were involved in severe children than in non-severe children, which was only risk factor associated with severe COVID-19 pneumonia in multivariable analysis. CONCLUSIONS: More than 3 lung segments involved were associated with greater risk of development of severe COVID-19 in children. Moreover, the possible risk of the elevation of IL-6, high total bilirubin and D-dimer with univariable analysis could identify patients to be severe earlier.

Two novel ECHS1 variants, affecting splicing and reducing enzyme activity, is associated with mitochondrial encephalopathy in infant: a case report.

BACKGROUND: Short-chain enoyl-CoA hydratase (ECHS1) is a multifunctional mitochondrial matrix enzyme involved in the second step of mitochondrial fatty acid ß-oxidation. Mitochondrial diseases resulting from ECHS1 mutations are often characterised by encephalopathy, deafness, epilepsy, optic atrophy, cardiomyopathy, dystonia, and lactic acidosis. In this study, we report two novel heterogeneous variants, c.414 + 5G > A (in intron 3) and c.310C > G (in CDS), of ECHS1 in an infant with mitochondrial encephalopathy. CASE PRESENTATION: The two novel variants, c.414 + 5G > A (Chr10:135183403) in intron 3 and c.310C > G (Chr10:135183512) in CDS, were identified by next generation sequencing (NGS). A minigene assay was used to analyse the function of the c.414 + 5G > A variant. ECHS1 enzyme activity was measured by spectrophotometry in the patient-derived myoblasts. The 2-year old patient presented with mitochondrial encephalopathy since birth. Clinical features were encephalopathy, epilepsy, and hindered psychomotor and language development. Serum lactate and blood ammonia levels were elevated, and brain magnetic resonance imaging showed abnormal signals in the bilateral frontal, parietal, and occipital cortices and brainstem and basal ganglia. We found two novel heterogeneous variants in ECHS1 in this patient. Minigene assay revealed the c.414 + 5G > A variant as the cause of intronic cryptic splice site activation and 39 bp deletion in mature mRNA. In silico analysis predicted that c.310C > G might change glutamine (Q) to glutamic acid (E) in the 104th amino acid sequence (p.Q104E). To investigate the impact of these two variants on protein function, we constructed a 3D model of human ECHS1 and showed that the variants might alter the highly conserved region in close proximity to the active site, which might hinder, or even halt, enzymatic activity. The experimental assay showed that ECHS1 enzyme activity in the patient-derived myoblasts decreased compared to that in control. CONCLUSIONS: Our findings are the first to report a mitochondrial encephalopathy infant carrying two novel ECHS1 variants, c.414 + 5G > A and c.310C > G, which might be deleterious variants, function as pathogenicity markers for mitochondrial encephalopathy, and facilitate disease diagnosis.

Canonical Transient Receptor Potential Channel 3 Contributes to Febrile Seizure Inducing Neuronal Cell Death and Neuroinflammation.

Febrile seizure (FS) counts as the most common seizures symptom in children undergoing recurrent seizures, posing a high risk to developing subsequent temporal lobe epilepsy. Canonical transient receptor potential channel (TRPC) members are identified as the FS-related genes in hyperthermia prone rats. However, the role of TRPC3 in hyperthermia-induced FS rats remains unclear. In the present study, we investigated whether TRPC3 functionally contributes to the development of FSs. Elevated TRPC3 mRNA and protein levels was detected in hyperthermia-induced FS rats and rat hippocampal neuron cells. The specific inhibitor of TRPC3, Pyr3, remarkably attenuated the susceptibility and severity of seizures, neuronal cell death, and neuroinflammation in FS rats. Conversely, NCX3 activation was apparently suppressed in rats subjected to recurrent FS and rat hippocampal neuron cells. The expression of NCX3 was up-regulated after TRPC3 inhibition in vivo and in vitro. Furthermore, an interaction between TRPC3 and NCX3 was detected by co-immunoprecipitation. Inhibition of TRPC3 suppressed intracellular Ca2+ levels in hyperthermia-treated hippocampal neuronal cells. In conclusion, our findings supported that TRPC3 functions as a critical regulator of seizure susceptibility and targeting TRPC3 may be a new therapeutic strategy for FS.