Syndrom Dravetové je závažnou vývojovou a epileptickou encefalopatií se začátkem v kojeneckém věku, která se projevuje farmakorezistentní epilepsií a četnými komorbiditami. Typická je provokace záchvatů zvýšenou teplotou. Léčba onemocnění je obtížná. V chronické medikaci by měl být první volbou valproát, dalšími přidanými léky klobazam, stiripentol, fenfluramin, kanabidiol, topiramát. Pacienti musí být vybaveni SOS medikací pro zvládnutí záchvatů v domácím prostředí. V léčbě je nutné se vyhnout blokátorům sodíkových kanálů, aplikace fenytoinu v epileptickém statu je však přípustná. Kromě protizáchvatové léčby je nutné věnovat pozornost i nefarmakologické léčbě komorbidit.

Dravet syndrome is a developmental and epileptic encephalopathy starting in infancy and its main features are drug -resistant epilepsy and several co-morbidities. Seizures are typically provoked by increased temperature. The treatment of Dravet syndrome is challenging. The first antiseizure drug should be valproic acid, while clobazam, stiripentol, fenfluramine, canabidiol or topiramate are usually added later. All the patients must have rescue medication for home management of seizures. Sodium channel blockers should not be used for chronic treatment, but phenytoin can be administered to stop status epilepticus. Non-pharmacological treatment of co-morbidities should be addressed as well.

• Klíčová slova
• stiripentol, fenfluramin,
• MeSH
• dioxolany aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• epilepsie myoklonické * farmakoterapie   patologie   MeSH
• kanabidiol aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• klobazam aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• komorbidita MeSH
• kyselina valproová aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• lidé MeSH
• selektivní inhibitory zpětného vychytávání serotoninu aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• topiramat aplikace a dávkování   farmakologie   terapeutické užití   MeSH
• Check Tag
• lidé MeSH

• MeSH
• diferenciální diagnóza MeSH
• epilepsie benigní neonatální * diagnóza   etiologie   farmakoterapie   klasifikace   MeSH
• lidé MeSH
• novorozenec MeSH
• prenatální diagnóza MeSH
• prognóza MeSH
• Check Tag
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• přehledy MeSH

Epilepsie jsou heterogenní skupinou onemocnění s významným etiologickým podílem patogenních variant v genech exprimovaných v centrálním nervovém systému. Monogenní epilepsie jsou jednotlivě vzácné, prevalence většiny z nich je neznámá, ale pravděpodobně je u většiny menší než 1 : 10 000. Prognózu mají různou v závislosti na postiženém genu a typu patogenní varianty. Ozřejmění genetické příčiny epilepsie může vést nejen ke stanovení rizika opakování epilepsie v rodině, ale v některých případech také k optimalizaci protizáchvatové medikace. V přehledovém článku přinášíme informace o vzácných geneticky podmíněných epilepsiích, u nichž může znalost patogenní varianty přispět k optimalizaci léčby.

Epilepsies are heterogeneous group of diseases with a significant etiological role of pathogenic variants in the genes expressed in the central nervous system. Monogenic epilepsies are individually rare, prevalence of most of them is unknown, but it is probably less than 1 : 10000. The outcome is variable, depending on the affected gene and type of the variant. The identification of the genetic causes of epilepsy can not only determine the risk of recurrence of epilepsy in the family, but in some cases also to optimize anti-seizure medication. In the overview article, we bring information about rare genetically conditioned epilepsies, in which knowledge of the pathogenic variant may contribute to the optimization of treatment.

Chromosomal band 17q12 is a gene-rich region flanked by segmental duplications, making the region prone to deletions and duplications via the non-allelic homologous recombination mechanism. While deletions cause a well-described disorder with a specific phenotype called renal cysts and diabetes mellitus, the phenotype caused by reciprocal duplications is less specific, primarily because of variable expressivity, and incomplete penetrance. We present an unusual family with four children carrying the 17q12 microduplication inherited from their clinically healthy mother, who was a carrier of both the duplication and, interestingly, also of an atypical deletion of the 17q12 region. The duplication was inherited from her diabetic father and the deletion from her diabetic mother who also suffered from a renal disorder. Clinical manifestations in the family were variable, but all children showed some degree of a neurodevelopmental disorder, such as epilepsy, intellectual disability, delayed speech development, or attention deficit disorder. The simultaneous occurrence of a deletion and duplication in the same chromosomal region in one family is very rare, and to our knowledge, individuals carrying both a deletion and a duplication of this region have never been described.

• MeSH
• chromozomální delece MeSH
• duplikace chromozomů genetika   MeSH
• fenotyp MeSH
• lidé MeSH
• mentální retardace * genetika   MeSH
• mnohočetné abnormality * genetika   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

OBJECTIVE: Developmental and epileptic encephalopathies (DEEs) are a group of severe, early-onset epilepsies characterised by refractory seizures, developmental delay, or regression and generally poor prognosis. DEE are now known to have an identifiable molecular genetic basis and are usually examined using a gene panel. However, for many patients, the genetic cause has still not been identified. The aims of this study were to identify causal variants for DEE in patients for whom the previous examination with a gene panel did not determine their genetic diagnosis. It also aims for a detailed description and broadening of the phenotypic spectrum of several rare DEEs. METHODS: In the last five years (2015-2020), 141 patients from all over the Czech Republic were referred to our department for genetic testing in association with their diagnosis of epilepsy. All patients underwent custom-designed gene panel testing prior to enrolment into the study, and their results were inconclusive. We opted for whole exome sequencing (WES) to identify the cause of their disorder. If a causal or potentially causal variant was identified, we performed a detailed clinical evaluation and phenotype-genotype correlation study to better describe the specific rare subtypes. RESULTS: Explanatory causative variants were detected in 20 patients (14%), likely pathogenic variants that explain the epilepsy in 5 patients (3.5%) and likely pathogenic variants that do not fully explain the epilepsy in 11 patients (7.5%), and variants in candidate genes in 4 patients (3%). Variants were mostly de novo 29/40 (72.5%). SIGNIFICANCE: WES enables us to identify the cause of the disease in additional patients, even after gene panel testing. It is very important to perform a WES in DEE patients as soon as possible, since it will spare the patients and their families many years of a diagnostic odyssey. In particular, patients with rare epilepsies might significantly benefit from this approach, and we propose using WES as a new standard in the diagnosis of DEE instead of targeted gene panel testing.

• MeSH
• epilepsie generalizovaná * genetika   MeSH
• epilepsie * diagnóza   genetika   MeSH
• fenotyp MeSH
• genetické asociační studie MeSH
• genetické testování MeSH
• lidé MeSH
• sekvenování exomu MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND AND OBJECTIVES: KCNH5 encodes the voltage-gated potassium channel EAG2/Kv10.2. We aimed to delineate the neurodevelopmental and epilepsy phenotypic spectrum associated with de novo KCNH5 variants. METHODS: We screened 893 individuals with developmental and epileptic encephalopathies for KCNH5 variants using targeted or exome sequencing. Additional individuals with KCNH5 variants were identified through an international collaboration. Clinical history, EEG, and imaging data were analyzed; seizure types and epilepsy syndromes were classified. We included 3 previously published individuals including additional phenotypic details. RESULTS: We report a cohort of 17 patients, including 9 with a recurrent de novo missense variant p.Arg327His, 4 with a recurrent missense variant p.Arg333His, and 4 additional novel missense variants. All variants were located in or near the functionally critical voltage-sensing or pore domains, absent in the general population, and classified as pathogenic or likely pathogenic using the American College of Medical Genetics and Genomics criteria. All individuals presented with epilepsy with a median seizure onset at 6 months. They had a wide range of seizure types, including focal and generalized seizures. Cognitive outcomes ranged from normal intellect to profound impairment. Individuals with the recurrent p.Arg333His variant had a self-limited drug-responsive focal or generalized epilepsy and normal intellect, whereas the recurrent p.Arg327His variant was associated with infantile-onset DEE. Two individuals with variants in the pore domain were more severely affected, with a neonatal-onset movement disorder, early-infantile DEE, profound disability, and childhood death. DISCUSSION: We describe a cohort of 17 individuals with pathogenic or likely pathogenic missense variants in the voltage-sensing and pore domains of Kv10.2, including 14 previously unreported individuals. We present evidence for a putative emerging genotype-phenotype correlation with a spectrum of epilepsy and cognitive outcomes. Overall, we expand the role of EAG proteins in human disease and establish KCNH5 as implicated in a spectrum of neurodevelopmental disorders and epilepsy.

• MeSH
• dítě MeSH
• draslíkové kanály ether-a-go-go * genetika   MeSH
• epilepsie generalizovaná * genetika   MeSH
• epilepsie * genetika   MeSH
• fenotyp MeSH
• lidé MeSH
• mutace MeSH
• novorozenec MeSH
• záchvaty genetika   MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• novorozenec MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

Voltage-gated sodium channel β1 subunits are essential proteins that regulate excitability. They modulate sodium and potassium currents, function as cell adhesion molecules and regulate gene transcription following regulated intramembrane proteolysis. Biallelic pathogenic variants in SCN1B, encoding β1, are linked to developmental and epileptic encephalopathy 52, with clinical features overlapping Dravet syndrome. A recessive variant, SCN1B-c.265C>T, predicting SCN1B-p.R89C, was homozygous in two children of a non-consanguineous family. One child was diagnosed with Dravet syndrome, while the other had a milder phenotype. We identified an unrelated biallelic SCN1B-c.265C>T patient with a clinically more severe phenotype than Dravet syndrome. We used CRISPR/Cas9 to knock-in SCN1B-p.R89C to the mouse Scn1b locus (Scn1bR89/C89). We then rederived the line on the C57BL/6J background to allow comparisons between Scn1bR89/R89 and Scn1bC89/C89 littermates with Scn1b+/+ and Scn1b-/- mice, which are congenic on C57BL/6J, to determine whether the SCN1B-c.265C>T variant results in loss-of-function. Scn1bC89/C89 mice have normal body weights and ∼20% premature mortality, compared with severely reduced body weight and 100% mortality in Scn1b-/- mice. β1-p.R89C polypeptides are expressed in brain at comparable levels to wild type. In heterologous cells, β1-p.R89C localizes to the plasma membrane and undergoes regulated intramembrane proteolysis similar to wild type. Heterologous expression of β1-p.R89C results in sodium channel α subunit subtype specific effects on sodium current. mRNA abundance of Scn2a, Scn3a, Scn5a and Scn1b was increased in Scn1bC89/C89 somatosensory cortex, with no changes in Scn1a. In contrast, Scn1b-/- mouse somatosensory cortex is haploinsufficient for Scn1a, suggesting an additive mechanism for the severity of the null model via disrupted regulation of another Dravet syndrome gene. Scn1bC89/C89 mice are more susceptible to hyperthermia-induced seizures at post-natal Day 15 compared with Scn1bR89/R89 littermates. EEG recordings detected epileptic discharges in young adult Scn1bC89/C89 mice that coincided with convulsive seizures and myoclonic jerks. We compared seizure frequency and duration in a subset of adult Scn1bC89/C89 mice that had been exposed to hyperthermia at post-natal Day 15 versus a subset that were not hyperthermia exposed. No differences in spontaneous seizures were detected between groups. For both groups, the spontaneous seizure pattern was diurnal, occurring with higher frequency during the dark cycle. This work suggests that the SCN1B-c.265C>T variant does not result in complete loss-of-function. Scn1bC89/C89 mice more accurately model SCN1B-linked variants with incomplete loss-of-function compared with Scn1b-/- mice, which model complete loss-of-function, and thus add to our understanding of disease mechanisms as well as our ability to develop new therapeutic strategies.

• Publikační typ
• časopisecké články MeSH

• MeSH
• komunikace MeSH
• lidé MeSH
• mladiství MeSH
• neinvazivní ventilace MeSH
• neuromuskulární nemoci komplikace   MeSH
• obstrukční spánková apnoe terapie   MeSH
• paliativní péče MeSH
• sdílené rozhodování * MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• Publikační typ
• kazuistiky MeSH

BACKGROUND: Schimke immunoosseous dysplasia (SIOD) is an ultra-rare inherited disease affecting many organ systems. Spondyloepiphyseal dysplasia, T-cell immunodeficiency and steroid resistant nephrotic syndrome are the main symptoms of this disease. CASE PRESENTATION: We aimed to characterize the clinical, pathological and genetic features of SIOD patients received at tertiary Pediatric Nephrology Center, University Hospital Motol, Prague, Czech Republic during the period 2001-2021. The mean age at diagnosis was 21 months (range 18-48 months). All patients presented with growth failure, nephropathy and immunodeficiency. Infections and neurologic complications were present in most of the affected children during the course of the disease. CONCLUSIONS: Although SIOD is a disease characterized by specific features, the individual phenotype may differ. Neurologic signs can severely affect the quality of life; the view on the management of SIOD is not uniform. Currently, new therapeutic methods are required.

• MeSH
• centra terciární péče MeSH
• kvalita života MeSH
• lidé MeSH
• nefrotický syndrom * diagnóza   genetika   komplikace   MeSH
• osteochondrodysplazie * diagnóza   genetika   terapie   MeSH
• syndromy imunologické nedostatečnosti * diagnóza   genetika   komplikace   MeSH
• vzácné nemoci MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• kazuistiky MeSH
• Geografické názvy
• Česká republika MeSH

We report detailed functional analyses and genotype-phenotype correlations in 392 individuals carrying disease-causing variants in SCN8A, encoding the voltage-gated Na+ channel Nav1.6, with the aim of describing clinical phenotypes related to functional effects. Six different clinical subgroups were identified: Group 1, benign familial infantile epilepsy (n = 15, normal cognition, treatable seizures); Group 2, intermediate epilepsy (n = 33, mild intellectual disability, partially pharmaco-responsive); Group 3, developmental and epileptic encephalopathy (n = 177, severe intellectual disability, majority pharmaco-resistant); Group 4, generalized epilepsy (n = 20, mild to moderate intellectual disability, frequently with absence seizures); Group 5, unclassifiable epilepsy (n = 127); and Group 6, neurodevelopmental disorder without epilepsy (n = 20, mild to moderate intellectual disability). Those in Groups 1-3 presented with focal or multifocal seizures (median age of onset: 4 months) and focal epileptiform discharges, whereas the onset of seizures in patients with generalized epilepsy was later (median: 42 months) with generalized epileptiform discharges. We performed functional studies expressing missense variants in ND7/23 neuroblastoma cells and primary neuronal cultures using recombinant tetrodotoxin-insensitive human Nav1.6 channels and whole-cell patch-clamping. Two variants causing developmental and epileptic encephalopathy showed a strong gain-of-function (hyperpolarizing shift of steady-state activation, strongly increased neuronal firing rate) and one variant causing benign familial infantile epilepsy or intermediate epilepsy showed a mild gain-of-function (defective fast inactivation, less increased firing). In contrast, all three variants causing generalized epilepsy induced a loss-of-function (reduced current amplitudes, depolarizing shift of steady-state activation, reduced neuronal firing). Functional effects were known for 170 individuals. All 136 individuals carrying a functionally tested gain-of-function variant had either focal (n = 97, Groups 1-3) or unclassifiable (n = 39) epilepsy, whereas 34 individuals with a loss-of-function variant had either generalized (n = 14), no (n = 11) or unclassifiable (n = 6) epilepsy; only three had developmental and epileptic encephalopathy. Computational modelling in the gain-of-function group revealed a significant correlation between the severity of the electrophysiological and clinical phenotypes. Gain-of-function variant carriers responded significantly better to sodium channel blockers than to other anti-seizure medications, and the same applied for all individuals in Groups 1-3. In conclusion, our data reveal clear genotype-phenotype correlations between age at seizure onset, type of epilepsy and gain- or loss-of-function effects of SCN8A variants. Generalized epilepsy with absence seizures is the main epilepsy phenotype of loss-of-function variant carriers and the extent of the electrophysiological dysfunction of the gain-of-function variants is a main determinant of the severity of the clinical phenotype in focal epilepsies. Our pharmacological data indicate that sodium channel blockers present a treatment option in SCN8A-related focal epilepsy with onset in the first year of life.

• MeSH
• blokátory sodíkových kanálů terapeutické užití   MeSH
• epilepsie generalizovaná * farmakoterapie   genetika   MeSH
• epileptické syndromy * farmakoterapie   genetika   MeSH
• genetické asociační studie MeSH
• kojenec MeSH
• lidé MeSH
• mentální retardace * genetika   MeSH
• mutace MeSH
• napěťově řízený sodíkový kanál, typ 6 * genetika   MeSH
• prognóza MeSH
• záchvaty farmakoterapie   genetika   MeSH
• Check Tag
• kojenec MeSH
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH