170,168 research outputs found
Severe myoclonic epilepsy in infancy (Dravet syndrome) 30 years later.
No full textDravet syndrome was described in 1978 by Dravet (1978) under the name of severe myoclonic epilepsy in infancy (SMEI). The characteristics of the syndrome were confirmed and further delineated by other authors over the years. According to the semiologic features, two forms have been individualized: (1) the typical, core, SMEI; and (2) the borderline form, SMEIB, in which the myoclonic component is absent or subtle. Clinical manifestations at the onset, at the steady state, and during the course of the disease are analyzed in detail for the typical Dravet syndrome, and the differential diagnosis is discussed. Onset in the first year of life by febrile or afebrile clonic and tonic-clonic, generalized, and unilateral seizures, often prolonged, in an apparently normal infant is the first symptom, suggesting the diagnosis. Later on, multiple seizure types, mainly myoclonic, atypical absences, and focal seizures appear, as well as a slowing of developmental and cognitive skills, and the appearance of behavioral disorders. Mutation screening for the SCN1A gene confirms the diagnosis in 70-80% of patients. All seizure types are pharmacoresistent, but a trend toward less severe epilepsy and cognitive impairment is usually observed after the age of 5 years
Early development in Dravet syndrome; visual function impairment precedes cognitive decline
No full textAim of the study was to describe prospectively the early neuropsychological evolution including the first pre-cognitive stages of the Severe Myoclonic Epilepsy in Infancy (SMEI) or Dravet syndrome. Five cases, four of whom since before a diagnostic evidence of the Dravet syndrome, were followed up. Full clinical assessment including developmental, visual function and behaviour assessments were serially performed. In four cases, a variable onset age of cognitive decline assessed with developmental scales was preceded some months before by an impairment of visual function; the remaining patient during all the course of follow-up till 51 months of age showed a normal development without visual impairment. A cognitive decline with variable onset was generally confirmed in Dravet syndrome. The previous early impairment of visual function seems to herald the cognitive decline and provides useful prognostic information; furthermore, it possibly suggests some clues for a better understanding of the mechanisms of cognitive deterioration in this syndrome
Cognitive development in Dravet syndrome: a retrospective, multicenter study of 26 patients
No full textTo clarify the role of epilepsy and genetic background in determining the cognitive outcome of patients with Dravet syndrome
Dravet syndrome as epileptic encephalopathy: Evidence from long-term course and neuropathology
No full textDravet syndrome is an epilepsy syndrome of infantile onset, frequently caused by SCN1A mutations or deletions. Its prevalence, long-term evolution in adults and neuropathology are not well known. We identified a series of 22 adult patients, including three adult post-mortem cases with Dravet syndrome. For all patients, we reviewed the clinical history, seizure types and frequency, antiepileptic drugs, cognitive, social and functional outcome and results of investigations. A systematic neuropathology study was performed, with post-mortem material from three adult cases with Dravet syndrome, in comparison with controls and a range of relevant paediatric tissue. Twenty-two adults with Dravet syndrome, 10 female, were included, median age 39 years (range 20–66). SCN1A structural variation was found in 60% of the adult Dravet patients tested, including one post-mortem case with DNA extracted from brain tissue. Novel mutations were described for 11 adult patients; one patient had three SCN1A mutations. Features of Dravet syndrome in adulthood include multiple seizure types despite polytherapy, and age-dependent evolution in seizure semiology and electroencephalographic pattern. Fever sensitivity persisted through adulthood in 11 cases. Neurological decline occurred in adulthood with cognitive and motor deterioration. Dysphagia may develop in or after the fourth decade of life, leading to significant morbidity, or death. The correct diagnosis at an older age made an impact at several levels. Treatment changes improved seizure control even after years of drug resistance in all three cases with sufficient follow-up after drug changes were instituted; better control led to significant improvement in cognitive performance and quality of life in adulthood in two cases. There was no histopathological hallmark feature of Dravet syndrome in this series. Strikingly, there was remarkable preservation of neurons and interneurons in the neocortex and hippocampi of Dravet adult post-mortem cases. Our study provides evidence that Dravet syndrome is at least in part an epileptic encephalopathy
Cognitive decline in Dravet syndrome: is there a cerebellar role?
No full textThe aim of the study was to perform a detailed assessment of cognitive abilities and behaviour in a series of epileptic patients with Dravet syndrome (DS) in order to establish a possible cerebellar-like pattern
Transcranial static magnetic stimulation reduces seizures in a mouse model of Dravet syndrome
No full text[Abstract] Dravet syndrome is a rare form of severe genetic epilepsy characterized by recurrent and long-lasting seizures. It appears around the first year of life, with a quick evolution toward an increase in the frequency of the seizures, accompanied by a delay in motor and cognitive development, and does not respond well to antiepileptic medication. Most patients carry a mutation in the gene SCN1A encoding the α subunit of the voltage-gated sodium channel Nav1.1, resulting in hyperexcitability of neural circuits and seizure onset. In this work, we applied transcranial static magnetic stimulation (tSMS), a non-invasive, safe, easy-to-use and affordable neuromodulatory tool that reduces neural excitability in a mouse model of Dravet syndrome. We demonstrate that tSMS dramatically reduced the number of crises. Furthermore, crises recorded in the presence of the tSMS were shorter and less intense than in the sham condition. Since tSMS has demonstrated its efficacy at reducing cortical excitability in humans without showing unwanted side effects, in an attempt to anticipate a possible use of tSMS for Dravet Syndrome patients, we performed a numerical simulation in which the magnetic field generated by the magnet was modeled to estimate the magnetic field intensity reached in the cerebral cortex, which could help to design stimulation strategies in these patients. Our results provide a proof of concept for nonpharmacological treatment of Dravet syndrome, which opens the door to the design of new protocols for treatment.info:eu-repo/grantAgreement/ISCIII/Programa Estatal de Generación de Conocimiento y Fortalecimiento del Sistema Español de I+D+I/PI21%2F00151/ES/CAMPOS MAGNETICOS ESTATICOS COMO TERAPIA INNOVADORA PARA LA EPILEPSIA REFRACTARIA Y EL SINDROME DE DRAVET; INVESTIGACION EXPERIMENTAL, NUMÉRICA Y CLINICA.Xunta de Galicia; ED431C 2022/05 (CR)Ministerio de Ciencia e Innovacion (España); PID2019-108250RJ-10
Molecular aspects of Dravet syndrome patients in Taiwan
No full textBackground: Dravet syndrome (DS) is a rare form of intractable epilepsy. Children with DS often start having seizures in infancy, and gradually develop other seizure types. Several studies have demonstrated that certain gene mutations and submicroscopic copy number variations (CNV) in DS patients are strongly associated with intractable epilepsy. In this study, directed DNA sequencing and microarray technology were used to investigate genomic variations in DS patients.
Methods: A total of nine DS patients were enrolled in this genetic study. A detailed medical history was obtained from each participant, and appropriate neurological examinations performed. Seizure types and epilepsy syndromes were classified according to ILAE criteria. The complete coding regions of SCNIA, SCN1B, SCN2A, GA13RG2, and GABRD, including the intron/exon boundaries, were sequenced using DNA samples drawn from participants. In addition, whole genome CNV analysis was conducted via SNP microarray analysis.
Results: DNA sequencing revealed a mutation in the SCN1A gene in five (55.6%) of the DS patients, within which three missense mutations, c719T > C (p.Leu240Pro), c2807A > T (pAsp936Val), c4349A > C (p.G1n1450Pro), and two frameshift mutations, c.2277insAACA (p.His759fsX772) and c.3972insT (p.Leu1324fsX1331) were observed. Upon CNV analysis, a novel duplication region, 4q13.1-q13.2, was detected in one DS patient; this variant region contained a gene, EPHA5, related to cerebral neuron development.
Conclusion: This study extended the spectrum of SCN1A mutations in Taiwanese DS patients and confirms the high sensitivity of SCN1A for the DS phenotype. In addition, a novel duplication region identified within EPHA5 should be considered in future screening procedures for DS. (C) 2013 Elsevier B.V. All rights reserved
A novel GABAergic dysfunction in human Dravet syndrome
No full textObjective Dravet syndrome is a rare neurodevelopmental disease, characterized by general cognitive impairment and severe refractory seizures. The majority of patients carry the gene mutation SCN1A, leading to a defective sodium channel that contributes to pathogenic brain excitability. A gamma-aminobutyric acid (GABAergic) impairment, as in other neurodevelopmental diseases, has been proposed as an additional mechanism, suggesting that seizures could be alleviated by GABAergic therapies. However, up to now the physiological mechanisms underlying the GABAergic dysfunction in Dravet syndrome are still unknown due to the scarce availability of this brain tissue. Here we studied, for the first time, human GABA(A)-evoked currents using cortical brain tissue from Dravet syndrome patients. Methods Results We transplanted in Xenopus oocytes cell membranes obtained from brain tissues of autopsies of Dravet syndrome patients, tuberous sclerosis complex patients as a pathological comparison, and age-matched controls. Additionally, experiments were performed on oocytes expressing human alpha 1 beta 2 gamma 2 and alpha 1 beta 2 GABA(A) receptors. GABA(A) currents were recorded using the two-microelectrodes voltage-clamp technique. Quantitative real-time polymerase chain reaction, immunohistochemistry, and double-labeling techniques were carried out on the same tissue samples. We found (1) a decrease in GABA sensitivity in Dravet syndrome compared to controls, which was related to an increase in alpha 4- relative to alpha 1-containing GABA(A) receptors; (2) a shift of the GABA reversal potential toward more depolarizing values in Dravet syndrome, and a parallel increase of the chloride transporters NKCC1/KCC2 expression ratio; (3) an increase of GABA(A) currents induced by low doses of cannabidiol both in Dravet syndrome and tuberous sclerosis complex comparable to that induced by a classical benzodiazepine, flunitrazepam, that still persists in gamma-less GABA(A) receptors. Significance Our study indicates that a dysfunction of the GABAergic system, considered as a feature of brain immaturity, together with defective sodium channels, can contribute to a general reduction of inhibitory efficacy in Dravet brain, suggesting that GABA(A) receptors could be a target for new therapies
Genetic therapeutic advancements for Dravet Syndrome
No full textDravet Syndrome is a genetic epileptic syndrome characterized by severe and intractable seizures associated with cognitive, motor, and behavioral impairments. The disease is also linked with increased mortality mainly due to sudden unexpected death in epilepsy. Over 80% of cases are due to a de novo mutation in one allele of the SCN1A gene, which encodes the α-subunit of the voltage-gated ion channel NaV1.1. Dravet Syndrome is usually refractory to antiepileptic drugs, which only alleviate seizures to a small extent. Viral, non-viral genetic therapy, and gene editing tools are rapidly enhancing and providing new platforms for more effective, alternative medicinal treatments for Dravet syndrome. These strategies include gene supplementation, CRISPR-mediated transcriptional activation, and the use of antisense oligonucleotides. In this review, we summarize our current knowledge of novel genetic therapies that are currently under development for Dravet syndrome
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