Dravet syndrome: Advances in etiology, clinical presentation, and treatment.

Dravet syndrome (DS) is a form of genetic refractory epilepsy. More than 80 % of DS patients carry pathogenic SCN1A mutations, and this percentage is actually higher due to false-negative results in gene testing. Potential genotype-phenotype correlations may exist but require further confirmation. "SCN1A mutation-mediated dysfunction of NaV1.1 affects GABAergic inhibitory interneurons" is currently the most accepted pathogenesis. Besides SCN1A, there are other genes associated with DS-like phenotypes, among which GABAA-receptor subunit genes have recently received more attention. Most DS patients experience prolonged, hemiclonic or tonic-clonic seizures triggered by fever during the first year of life, followed by the gradual onset of other seizure types, including myoclonic, atypical absence, and focal seizures. Over time, seizures tend to become less frequent and severe but generalized tonic-clonic seizures remain. DS also has many comorbidities, including motor, cognitive, behavior, and sleep impairments, which cause poor quality of life and impact the long-term course. The electroencephalography and neuroimaging of DS lack specificity, but the evolution of electroencephalography may help to identify DS. Current treatments for DS are symptomatic and difficult to control seizures. The combination of valproic acid, clobazam and stiripentol is a commonly used clinical treatment option, fenfluramine and cannabidiol have been used as second- and third-line drugs, respectively. Later therapeutic options include other anti-seizure medications, the ketogenic diet, and vagus nerve stimulation, whereas sodium channel blockers should be avoided in DS. Furthermore, several promising drugs including soticlestat are in development, and genetic therapies are beginning to emerge, representing future treatment directions.

Long-term outcome of developmental and epileptic encephalopathies.

Developmental and epileptic encephalopathies are conditions where there is developmental impairment related to both the underlying etiology independent of epileptiform activity and the epileptic encephalopathy. Usually they have multiple etiologies. Therefore, long-term outcome is related to both etiology-related factors and epilepsy-related factors-age at onset of epilepsy, type(s) of seizure(s), type of electroencephalographic abnormalities, duration of the epileptic disorder. This paper focuses on long-term outcome of six developmental and epileptic encephalopathies with onset from the neonatal period to childhood: early epileptic encephalopathy with suppression bursts, West syndrome, Dravet syndrome, Lennox-Gastaut syndrome, epilepsy with myoclonic atonic seizures and epileptic encephalopathy with continuous spike and waves during slow-wave sleep including Landau-Kleffner syndrome. For each syndrome, definition, main etiologies if multiple, and long-term outcome are discussed.

COVID-19 vaccine in patients with Dravet syndrome: Observations and real-world experiences.

OBJECTIVE: Vaccination against the SARS-CoV-2 virus is a primary tool to combat the COVID-19 pandemic. However, vaccination is a common seizure trigger in individuals with Dravet syndrome (DS). Information surrounding COVID-19 vaccine side effects in patients with DS would aid caregivers and providers in decisions for and management of COVID-19 vaccination. METHODS: A survey was emailed to the Dravet Syndrome Foundation's Family Network and posted to the Dravet Parent & Caregiver Support Group on Facebook between May and August 2021. Deidentified information obtained included demographics and vaccination status for individuals with DS. Vaccine type, side effects, preventative measures, and changes in seizure activity following COVID-19 vaccination were recorded. For unvaccinated individuals, caregivers were asked about intent to vaccinate and reasons for their decision. RESULTS: Of 278 survey responses, 120 represented vaccinated individuals with DS (median age = 19.5 years), with 50% reporting no side effects from COVID-19 vaccination. Increased seizures following COVID-19 vaccination were reported in 16 individuals, but none had status epilepticus. Of the 158 individuals who had not received a COVID-19 vaccination, 37 were older than 12 years (i.e., eligible at time of study), and only six of these caregivers indicated intent to seek vaccination. The remaining 121 responses were caregivers to children younger than 12 years, 60 of whom indicated they would not seek COVID-19 vaccination when their child with DS became eligible. Reasons for vaccine hesitancy were fear of increased seizure activity and concerns about vaccine safety. SIGNIFICANCE: These results indicate COVID-19 vaccination is well tolerated by individuals with DS. One main reason for vaccine hesitancy was fear of increased seizure activity, which occurred in only 13% of vaccinated individuals, and none had status epilepticus. This study provides critical and reassuring insights for caregivers and health care providers making decisions about the safety of COVID-19 vaccinations for individuals with DS.

The relationship between the characteristics of burst suppression pattern and different etiologies in epilepsy.

To analyze the relationship between the characteristics of burst suppression (BS) pattern and different etiologies in epilepsy. Patients with a BS pattern who were younger than 6 months old were screened from our electroencephalogram (EEG) database. The synchronized and symmetric BS patterns under different etiologies in epilepsy were analyzed. A total of 32 patients had a BS pattern on EEG. The etiologies included genetic disorders (37.5%), cortical malformations (28.1%), inborn errors of metabolism (12.5%), and unknown (21.9%). Twenty-five patients were diagnosed with Ohtahara syndrome, one as early myoclonic encephalopathy, and one as epilepsy of infancy with migrating focal seizure. Five cases could not be classified into any epileptic syndrome. Asynchronous BS pattern was identified in 18 cases, of which 13 (72%) patients had genetic and/or metabolic etiologies. Synchronous BS pattern was identified in 14 cases, of which 8 (57%) patients had structural etiologies. Twenty-three patients had symmetric BS patterns, of which 15 (65%) patients had genetic etiologies. Nine patients had asymmetric BS patterns, of which 8 (89%) patients had structural etiologies. Patients with genetic epilepsies tended to have asynchronous and symmetric BS patterns, whereas those with structural epilepsies were more likely to have synchronous and asymmetric BS patterns.

CRISPRa-Mediated Upregulation of scn1laa During Early Development Causes Epileptiform Activity and dCas9-Associated Toxicity.

Dravet syndrome (DS) is a monogenic epileptic encephalopathy caused by loss-of-function mutations in the voltage-gated sodium channel (VGSC) gene SCN1A. DS has an age of onset within the first year of life and severe disease prognosis. In the past years, it has been shown that upregulation of endogenous SCN1A can be beneficial in animal models for DS, but a complete rescue was not observed. We hypothesized that upregulation during early development that precedes onset of first symptoms might improve disease outcome. To test this hypothesis, we first evaluated the CRISPR activating method for early upregulation of voltage gated sodium channels during early development. We injected CRISPRa components, which target the proximal or distal promoter region of the VGSC gene scn1Laa in the yolk of one-cell stage zebrafish embryos. The effect of both dCas9-VPR and dCas9-VP64 was evaluated. Both CRISPRa fusions showed toxicity in the majority of embryos, with or without guide RNAs. The few embryos that survived developed normally, and dCas9-VPR induces an upregulation of scn1Laa mRNA until 24 hours after fertilization. At 5 days post fertilization, CRISPRa-injected embryos showed an epileptic phenotype, including locomotor burst movements, hyperactivity, and epileptiform activity originating from the brain. In addition to previously published scn1Laa and scn1Lab loss-of-function models, we conclude that gain of scn1Laa function can have an equally severe phenotype. Upregulation of scn1Laa in the current zebrafish model for DS, scn1Lab-KO, aggravated the disease phenotype, highlighting that early-stage upregulation using CRISPRa can lead to both toxicity and a worsening of the disease phenotype.

CSNK2B: A broad spectrum of neurodevelopmental disability and epilepsy severity.

CSNK2B has recently been implicated as a disease gene for neurodevelopmental disability (NDD) and epilepsy. Information about developmental outcomes has been limited by the young age and short follow-up for many of the previously reported cases, and further delineation of the spectrum of associated phenotypes is needed. We present 25 new patients with variants in CSNK2B and refine the associated NDD and epilepsy phenotypes. CSNK2B variants were identified by research or clinical exome sequencing, and investigators from different centers were connected via GeneMatcher. Most individuals had developmental delay and generalized epilepsy with onset in the first 2 years. However, we found a broad spectrum of phenotypic severity, ranging from early normal development with pharmacoresponsive seizures to profound intellectual disability with intractable epilepsy and recurrent refractory status epilepticus. These findings suggest that CSNK2B should be considered in the diagnostic evaluation of patients with a broad range of NDD with treatable or intractable seizures.

The severe epilepsy syndromes of infancy: A population-based study.

OBJECTIVE: To study the epilepsy syndromes among the severe epilepsies of infancy and assess their incidence, etiologies, and outcomes. METHODS: A population-based cohort study was undertaken of severe epilepsies with onset before age 18 months in Victoria, Australia. Two epileptologists reviewed clinical features, seizure videos, and electroencephalograms to diagnose International League Against Epilepsy epilepsy syndromes. Incidence, etiologies, and outcomes at age 2 years were determined. RESULTS: Seventy-three of 114 (64%) infants fulfilled diagnostic criteria for epilepsy syndromes at presentation, and 16 (14%) had "variants" of epilepsy syndromes in which there was one missing or different feature, or where all classical features had not yet emerged. West syndrome (WS) and "WS-like" epilepsy (infantile spasms without hypsarrhythmia or modified hypsarrhythmia) were the most common syndromes, with a combined incidence of 32.7/100 000 live births/year. The incidence of epilepsy of infancy with migrating focal seizures (EIMFS) was 4.5/100 000 and of early infantile epileptic encephalopathy (EIEE) was 3.6/100 000. Structural etiologies were common in "WS-like" epilepsy (100%), unifocal epilepsy (83%), and WS (39%), whereas single gene disorders predominated in EIMFS, EIEE, and Dravet syndrome. Eighteen (16%) infants died before age 2 years. Development was delayed or borderline in 85 of 96 (89%) survivors, being severe-profound in 40 of 96 (42%). All infants with EIEE or EIMFS had severe-profound delay or were deceased, but only 19 of 64 (30%) infants with WS, "WS-like," or "unifocal epilepsy" had severe-profound delay, and only two of 64 (3%) were deceased. SIGNIFICANCE: Three quarters of severe epilepsies of infancy could be assigned an epilepsy syndrome or "variant syndrome" at presentation. In this era of genomic testing and advanced brain imaging, diagnosing epilepsy syndromes at presentation remains clinically useful for guiding etiologic investigation, initial treatment, and prognostication.

Two different missense mutations of PEX genes in two similar patients with severe Zellweger syndrome: an argument on the genotype-phenotype correlation.

Background Peroxisomal biogenesis disorders (PBDs) include a miscellaneous group of diseases which cause serious multisystem disease. Mutations of 13 different PEX genes lead to PBDs including Zellweger syndrome (ZS). Different types of mutations of PEX1 and PEX10 genes are correlated with broad-range phenotypes of PBDs. Case presentation Patient 1 is a 4-month-old boy who was affected by myoclonic seizures, poor oral feeding since birth. The patient was hypotonic and had hepatosplenomegaly. Patient 2 is a 2-month-old boy who presented with decreased movement, severe hypotonia and failure to thrive. The laboratory studies of the patients revealed increased plasma very-long-chain fatty acids (VLCFAs). The genetic analyses of patient 1 demonstrated the first homozygous missense mutation in the PEX10 gene. A novel homozygous missense mutation was found in the PEX1 gene in patient 2. Conclusions This report highlights that the detected homozygous missense mutations of PEX10 and PEX1 genes and the substitutions of specific amino acids lead to the severe form of PBDs.

Inducción de crisis de ausencia atípica durante el tratamiento con perampanel / Induced atypical absence seizures during treatment with perampanel

No disponible

Cleft Palate as Distinguishing Feature in a Patient with GABRB3 Epileptic Encephalopathy.

Mutations in GABAA-receptor subunit genes are associated with a heterogeneous spectrum of epilepsies. Patients with epilepsy caused by mutations in a specific GABAA-receptor (GABRA3) occasionally present with orofacial dysmorphism (e.g., cleft palates). While cleft palates have been described in Gabrb3 knockout mice and in humans with GABRB3 variants without epilepsy, the specific combination of epilepsy and cleft palate in humans with GABRB3 mutations has not yet been reported.We describe a patient with epileptic encephalopathy (EE) who presented with therapy-refractory neonatal-onset myoclonic seizures and severe developmental delay. Electroencephalogram showed burst suppression pattern at neonatal age and hypsarrhythmia at infantile age. Initial magnetic resonance imaging was unremarkable. As he additionally presented with a cleft palate, we were curious whether cleft palate and EE had the same genetic origin. Whole exome sequencing of the index patient revealed a novel pathogenic heterozygous de novo mutation in GABRB3 (c.899T > C; p.I300T). In consistency with Gabrb3 knockout mice data, this is the first report of cleft palate in a patient with GABRB3 associated EE.We suggest to add cleft palate to the phenotypic GABRB3 spectrum and to screen for mutations in GABAA-receptors in patients with EE and orofacial dysmorphism.

Delayed maturation of GABAergic signaling in the Scn1a and Scn1b mouse models of Dravet Syndrome.

Dravet syndrome (DS) is a catastrophic developmental and epileptic encephalopathy characterized by severe, pharmacoresistant seizures and the highest risk of Sudden Unexpected Death in Epilepsy (SUDEP) of all epilepsy syndromes. Here, we investigated the time course of maturation of neuronal GABAergic signaling in the Scn1b-/- and Scn1a+/- mouse models of DS. We found that GABAergic signaling remains immature in both DS models, with a depolarized reversal potential for GABAA-evoked currents compared to wildtype in the third postnatal week. Treatment of Scn1b-/- mice with bumetanide resulted in a delay in SUDEP onset compared to controls in a subset of mice, without prevention of seizure activity or amelioration of failure to thrive. We propose that delayed maturation of GABAergic signaling may contribute to epileptogenesis in SCN1B- and SCN1A-linked DS. Thus, targeting the polarity of GABAergic signaling in brain may be an effective therapeutic strategy to reduce SUDEP risk in DS.

FUS-ALS presenting with myoclonic jerks in a 17-year-old man.

Fused in sarcoma-related amyotrophic lateral sclerosis (FUS-ALS) accounts for 4% of all familial motor neurone disease, but has a much higher incidence in juvenile ALS. We present a case of a 17-year-old British man with rapidly progressive bulbar and respiratory failure. On examination he had weak periocular muscles, neck flexion weakness, and a wasted, fasciculating and weak tongue. There were no sensory, cerebellar, or extrapyramidal features but he had frequent myoclonic jerks of the limbs. Routine bloods were normal and an MRI of the neuroaxis as well as CT chest, abdomen and pelvis were unremarkable. NCS/EMG was consistent with anterior horn cell disorder and EEG showed multiple paroxysmal generalized spike-wave discharges. DNA sequencing demonstrated that he was heterozygous for the c.1483C>T pathogenic nonsense mutation in exon 14 of the FUS gene, consistent with ALS6. This is the first reported case of FUS-ALS presenting with prominent myoclonus.

Expansions of intronic TTTCA and TTTTA repeats in benign adult familial myoclonic epilepsy.

Epilepsy is a common neurological disorder, and mutations in genes encoding ion channels or neurotransmitter receptors are frequent causes of monogenic forms of epilepsy. Here we show that abnormal expansions of TTTCA and TTTTA repeats in intron 4 of SAMD12 cause benign adult familial myoclonic epilepsy (BAFME). Single-molecule, real-time sequencing of BAC clones and nanopore sequencing of genomic DNA identified two repeat configurations in SAMD12. Intriguingly, in two families with a clinical diagnosis of BAFME in which no repeat expansions in SAMD12 were observed, we identified similar expansions of TTTCA and TTTTA repeats in introns of TNRC6A and RAPGEF2, indicating that expansions of the same repeat motifs are involved in the pathogenesis of BAFME regardless of the genes in which the expanded repeats are located. This discovery that expansions of noncoding repeats lead to neuronal dysfunction responsible for myoclonic tremor and epilepsy extends the understanding of diseases with such repeat expansion.

Early infancy-onset stimulation-induced myoclonic seizures in three siblings with inherited glycosylphosphatidylinositol (GPI) anchor deficiency.

Inherited glycosylphosphatidylinositol anchor deficiency causes a variety of clinical symptoms, including epilepsy, however, little information is available regarding seizures as a symptom. We report three siblings with inherited glycosylphosphatidylinositol anchor deficiency with PIGL gene mutations. The phenotypes of the subjects were not consistent with CHIME syndrome or Mabry syndrome, as reported in previous studies. All shared some clinical manifestations, including transient apnoea as neonates, dysmorphic facial features, and intellectual disability. Between one week and 3 months of life, all patients developed myoclonic seizures. Myoclonic jerks were easily evoked by sudden unexpected acoustic or tactile stimuli. None showed elevation of serum alkaline phosphatase. Vitamin B6 was given to one of the three siblings, but failed to suppress seizures. The presence of early infancy-onset stimulation-induced myoclonic seizures combined with dysmorphic facial features should lead physicians to consider the possibility of inherited glycosylphosphatidylinositol anchor deficiency.

[Myoclonus as a movement disorder]. / Myoklonien als Bewegungsstörung.

Myoclonus is often a diagnostic and therapeutic challenge due to its broad phenomenological variability and limited therapeutic options. This article gives a short survey and characterizes in detail two common types of myoclonus, cortical myoclonus and reticular reflex myoclonus. Clinical testing and electrophysiological investigations provide relevant local diagnostic indications for the generating structure(s). Such indications would influence not only the strategies of neuroimaging and laboratory investigations aimed at clarifying the underlying cause but also the selection of drugs to suppress myoclonus.

Myoclonic epilepsy in infancy with preceding or concurrent afebrile generalized tonic-clonic seizures in Chinese children.

OBJECTIVE: To investigate the general characteristics and the category of myoclonic epilepsy in infancy (MEI) with or without afebrile generalized tonic-clonic seizures (GTCS). METHODS: Thirty-three children were retrospectively recruited from approximately 42,814 video-electroencephalogram (VEEG) recordings monitored in our department over last nearly 10years. Myoclonic seizures (MS) must be identified by VEEG in all patients. The clinical, EEG features and outcome were analyzed among these patients. RESULTS: The 33 patients (25 boys and 8 girls) were divided into three groups: 11 patients with typical MEI; 16 patients with MEI experienced afebrile GTCS before MS onset; and 6 patients with MEI presented afebrile GTCS occurring concurrently with MS. No significant differences were found among the three groups, including gender distribution, family history, personal history of febrile seizures, the age at seizure onset and control, the duration of MS, the interval between age at onset and seizure control, the age at EEG normalization, the interval between seizure onset age and EEG normalization age and normal psychomotor development at the end of follow-up. More patients in group two and group three were controlled by two or three kinds of antiepileptic drugs compared with those in group one. CONCLUSIONS: In this study, three groups of patients had similar clinical, EEG features and outcome. Afebrile GTCS was associated with a stronger cortical hyperexcitability. It was worth considering whether MEI with preceding or concurrent afebrile GTCS should be recognized as subgroups or different epileptic syndromes independent of MEI.

A case of fulminant subacute sclerosing panencephalitis presenting with acute myoclonic-astatic epilepsy.

The neurologic sequelae post-measles are less common than other complications measles-related and can lead to severe disability or death: primary measles encephalitis (PME), acute post-infectious measles encephalomyelitis (APME), measles inclusion body encephalitis (MIBE), and subacute sclerosing panencephalitis (SSPE). SSPE syndrome can affect people years from the acute measles virus infection, as result of the persistence of defective viral particles in brain cells. Clinical onset typically manifests with progressive intellectual deterioration, behavioral changes, and myoclonic jerks. The course of SSPE in the majority of affected children is that of a progressive worsening with fatal outcome within two years. This report described an Italian case of fulminant SSPE syndrome that led to death within few months from the initial onset.