RESUMO
OBJECTIVE: Psychosis of epilepsy (POE) occurs more frequently in temporal lobe epilepsy, raising the question as to whether abnormalities of the hippocampus are aetiologically important. Despite decades of investigation, it is unclear whether hippocampal volume is reduced in POE, perhaps due to small sample sizes and methodological limitations of past research. METHODS: In this study, we examined the volume of the total hippocampus, and the hippocampal head, body and tail, in a large cohort of patients with POE and patients with epilepsy without psychosis (EC). One hundred adults participated: 50 with POE and 50 EC. Total and subregional hippocampal volumes were manually traced and compared between (1) POE and EC; (2) POE with temporal lobe epilepsy, extratemporal lobe epilepsy and generalised epilepsy; and (3) patients with POE with postictal psychosis (PIP) and interictal psychosis (IP). RESULTS: Compared with EC the POE group had smaller total left hippocampus volume (13.5% decrease, p<0.001), and smaller left hippocampal body (13.3% decrease, p=0.002), and left (41.5% decrease, p<0.001) and right (36.4% decrease, p<0.001) hippocampal tail volumes. Hippocampal head volumes did not differ between groups. CONCLUSION: Posterior hippocampal volumes are bilaterally reduced in POE. Volume loss was observed on a posteroanterior gradient, with severe decreases in the tail and moderate volume decreases in the body, with no difference in the hippocampal head. Posterior hippocampal atrophy is evident to a similar degree in PIP and IP. Our findings converge with those reported for the paradigmatic psychotic disorder, schizophrenia, and suggest that posterior hippocampal atrophy may serve as a biomarker of the risk for psychosis, including in patients with epilepsy.
Assuntos
Epilepsia/complicações , Hipocampo/patologia , Transtornos Psicóticos/etiologia , Adolescente , Adulto , Idoso , Estudos de Casos e Controles , Epilepsia/diagnóstico por imagem , Epilepsia/patologia , Epilepsia do Lobo Temporal/diagnóstico por imagem , Epilepsia do Lobo Temporal/patologia , Feminino , Hipocampo/diagnóstico por imagem , Humanos , Imageamento por Ressonância Magnética , Masculino , Pessoa de Meia-Idade , Neuroimagem , Tamanho do Órgão , Estudos Prospectivos , Transtornos Psicóticos/diagnóstico por imagem , Transtornos Psicóticos/patologia , Estudos Retrospectivos , Adulto JovemRESUMO
We sought to identify the molecular basis of the autosomal dominant form of Kufs disease, an adult onset form of neuronal ceroid lipofuscinosis. We used a combination of classic linkage analysis and Next Generation Sequencing to map and identify mutations in DNAJC5 in a total of three families. We analyzed the clinical manifestations in 20 individuals with mutation in DNAJC5. We report here the mapping and the identification of a p.L116del mutation in DNAJC5 segregating with the disease in two distinct American families, as well as a p.L115R mutation in an additional family. The age of onset and clinical manifestations were very homogeneous among mutation positive individuals, including generalized tonic-clonic seizures, myoclonus, ataxia, speech deterioration, dementia, and premature death. A few individuals also exhibited parkinsonism. DNAJC5, which encodes the cysteine string protein (CSPα), a presynaptic protein implicated in neurodegeneration, causes autosomal dominant Kufs disease. The leucine residues at positions 115 and 116 are hotspots for mutations and result in a homogeneous phenotype of progressive myoclonus epilepsy with onset around 30 years old.
Assuntos
Predisposição Genética para Doença/genética , Proteínas de Choque Térmico HSP40/genética , Proteínas de Membrana/genética , Mutação , Lipofuscinoses Ceroides Neuronais/genética , Adulto , Idade de Início , Sequência de Aminoácidos , Sequência de Bases , Análise Mutacional de DNA , Saúde da Família , Feminino , Genótipo , Humanos , Masculino , Pessoa de Meia-Idade , Lipofuscinoses Ceroides Neuronais/epidemiologia , Lipofuscinoses Ceroides Neuronais/patologia , Linhagem , Polimorfismo Genético , Deleção de SequênciaRESUMO
Epilepsy affects at least 2% of the population at some time in their lives. The epilepsies are a heterogeneous group of disorders, many with an inherited component. Although specific genes have been identified in a few rare diseases causing seizures as part of a more diffuse brain disorder, the molecular pathology of the common idiopathic epilepsies is still unknown. Linkage has been reported for some generalised epilepsy syndromes, but only very recently for familial partial epilepsy syndromes. Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) is a partial epilepsy causing frequent, violent, brief seizures at night, usually beginning in childhood. The gene for ADNFLE maps to chromosome 20q13.2-q13.3 in one large Australian kindred. The neuronal nicotinic acetylcholine receptor alpha 4 subunit (CHRNA4) maps to the same region of 20q (ref. 12) and the gene is expressed in all layers of the frontal cortex. We screened affected family members for mutations within CHRNA4 and found a missense mutation that replaces serine with phenylalanine at codon 248, a strongly conserved amino acid residue in the second transmembrane domain. The mutation is present in all 21 available affected family members and in four obligate carriers, but not in 333 healthy control subjects.
Assuntos
Cromossomos Humanos Par 20 , Epilepsia do Lobo Frontal/genética , Genes Dominantes , Mutação Puntual , Receptores Nicotínicos/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Galinhas , Mapeamento Cromossômico , Primers do DNA , Feminino , Lobo Frontal/metabolismo , Ligação Genética , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Reação em Cadeia da Polimerase , Ratos , Receptores Nicotínicos/química , Homologia de Sequência de AminoácidosRESUMO
The epilepsies comprise a group of syndromes that are divided into generalized and partial (focal) types. Familial occurrence has long been recognized but progress in mapping epilepsy genes has been slow except for rare cases where the inheritance is easily determined from classical genetic studies. Linkage is established for three generalized syndromes: the EBN1 and EBN2 genes for benign familial neonatal convulsions (BFNC) map to chromosomes 20q and 8q (refs 2-5), the EPM1 gene for Unverricht-Lundborg disease maps to 21q (ref. 6) and the gene for the northern epilepsy syndrome maps to 8p (ref. 7). A claim for linkage of the EJM1 gene for the common generalized syndrome of juvenile myoclonic epilepsy to 6p is currently in dispute. Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) was recently described in five families. We now report the chromosomal assignment, to 20q13.2, for the gene for ADNFLE in one large Australian kindred with 27 affected individuals spanning six generations.
Assuntos
Cromossomos Humanos Par 20 , Epilepsia do Lobo Frontal/genética , Epilepsia Generalizada/genética , Feminino , Ligação Genética , Marcadores Genéticos , Humanos , Masculino , Linhagem , Receptores Nicotínicos/genéticaRESUMO
Epilepsies affect at least 2% of the population at some time in life, and many forms have genetic determinants. We have found a mutation in a gene encoding a GABA(A) receptor subunit in a large family with epilepsy. The two main phenotypes were childhood absence epilepsy (CAE) and febrile seizures (FS). There is a recognized genetic relationship between FS and CAE, yet the two syndromes have different ages of onset, and the physiology of absences and convulsions is distinct. This suggests the mutation has age-dependent effects on different neuronal networks that influence the expression of these clinically distinct, but genetically related, epilepsy phenotypes. We found that the mutation in GABRG2 (encoding the gamma2-subunit) abolished in vitro sensitivity to diazepam, raising the possibility that endozepines do in fact exist and have a physiological role in preventing seizures.
Assuntos
Epilepsia Tipo Ausência/genética , Receptores de GABA-A/genética , Convulsões Febris/genética , Idade de Início , Anticonvulsivantes/farmacologia , Criança , Segregação de Cromossomos , Diazepam/farmacologia , Eletrofisiologia , Éxons , Feminino , Moduladores GABAérgicos/farmacologia , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Subunidades ProteicasRESUMO
Febrile seizures affect approximately 3% of all children under six years of age and are by far the most common seizure disorder. A small proportion of children with febrile seizures later develop ongoing epilepsy with afebrile seizures. Segregation analysis suggests the majority of cases have complex inheritance but rare families show apparent autosomal dominant inheritance. Two putative loci have been mapped (FEB1 and FEB2), but specific genes have not yet been identified. We recently described a clinical subset, termed generalized epilepsy with febrile seizures plus (GEFS+), in which many family members have seizures with fever that may persist beyond six years of age or be associated with afebrile generalized seizures. We now report linkage, in another large GEFS+ family, to chromosome region 19q13.1 and identification of a mutation in the voltage-gated sodium (Na+)-channel beta1 subunit gene (SCN1B). The mutation changes a conserved cysteine residue disrupting a putative disulfide bridge which normally maintains an extracellular immunoglobulin-like fold. Co-expression of the mutant beta1 subunit with a brain Na+-channel alpha subunit in Xenopus laevis oocytes demonstrates that the mutation interferes with the ability of the subunit to modulate channel-gating kinetics consistent with a loss-of-function allele. This observation develops the theme that idiopathic epilepsies are a family of channelopathies and raises the possibility of involvement of other Na+-channel subunit genes in febrile seizures and generalized epilepsies with complex inheritance patterns.
Assuntos
Epilepsia Generalizada/genética , Ligação Genética , Mutação Puntual/genética , Convulsões Febris/genética , Canais de Sódio/genética , Sequência de Aminoácidos , Animais , Cromossomos Humanos Par 19/genética , Análise Mutacional de DNA , Feminino , Humanos , Masculino , Dados de Sequência Molecular , Oócitos , Técnicas de Patch-Clamp , Linhagem , Canais de Sódio/fisiologia , Tasmânia , Xenopus laevisRESUMO
BACKGROUND/AIMS: Renin processing and storage is believed to occur in lysosome-like structures in the afferent arteriole. SCARB2/Limp-2 is a transmembrane lysosomal protein responsible for the intracellular trafficking of ß-glucocerebrosidase. This study aimed to confirm the expression of SCARB2/Limp-2 in renin secretory granules, and explore its role in renin processing and secretion. METHODS: Co-localisation studies of (pro)renin with lysosomal membrane proteins, SCARB2/Limp-2, LAMP-1 and LAMP-2, were performed in mouse and human kidney sections. Intrarenal expression and secretion of (pro)renin in wild-type (WT) and Limp-2(-/-) mice were compared with and without stimulation. RESULTS: SCARB2/Limp-2, LAMP-1 and LAMP-2 co-localised with (pro)- renin in mouse and human kidney. Plasma renin concentration was increased in Limp-2(-/-) mice when compared to WT littermates. No change in (pro)renin expression, however, was observed in Limp-2(-/-) mouse kidney cortex by immunofluorescence microscopy, Western blotting, quantitative RT-PCR or the ultrastructural appearance of renin secretory granules. Acute stimulation of renin release by isoprenaline or hydralazine was similar in WT and Limp-2(-/-) mice. Following chronic salt restriction, however, immunofluorescence microscopy showed less (pro)renin expressed in Limp-2(-/-) compared with WT mouse kidneys, and there was significantly less prorenin but not renin by Western blotting in Limp-2(-/-) mouse kidney cortex, despite no difference in circulating renin levels. CONCLUSION: Renin secretory granules possess integral lysosomal proteins, confirming that they are indeed modified lysosomes. Limp-2 deficiency leads to a minor increase in circulating renin. Limp-2, however, is not required for acute or chronic stimulation of renin release.
Assuntos
Arteríolas/metabolismo , Antígenos CD36/biossíntese , Proteínas de Membrana Lisossomal/biossíntese , Receptores Depuradores/biossíntese , Renina/metabolismo , Vesículas Secretórias/metabolismo , Animais , Feminino , Humanos , Rim/irrigação sanguínea , Proteína 2 de Membrana Associada ao Lisossomo , Lisossomos/metabolismo , Masculino , Camundongos , RatosRESUMO
Deficiency of the intrinsic lysosomal protein human scavenger receptor class B, member 2 (SCARB2; Limp-2 in mice) causes collapsing focal and segmental glomerular sclerosis (FSGS) and myoclonic epilepsy in humans, but patients with no apparent kidney damage have recently been described. We now demonstrate that these patients can develop tubular proteinuria. To determine the mechanism, mice deficient in Limp-2, the murine homolog of SCARB2, were studied. Most low-molecular-weight proteins filtered by the glomerulus are removed in the proximal convoluted tubule (PCT) by megalin/cubilin-dependent receptor-mediated endocytosis. Expression of megalin and cubilin was unchanged in Limp-2(-/-) mice, however, and the initial uptake of injected Alexa Fluor 555-conjugated bovine serum albumin (Alexa-BSA) was similar to wild-type mice, indicating that megalin/cubilin-dependent, receptor-mediated endocytosis was unaffected. There was a defect in proteolysis of reabsorbed proteins in the Limp-2(-/-) mice, demonstrated by the persistence of Alexa-BSA in the PCT compared with controls. This was associated with the failure of the lysosomal protease cathepsin B to colocalize with Alexa-BSA and endogenous retinol-binding protein in kidneys from Limp-2(-/-) mice. The data suggest that tubular proteinuria in Limp-2(-/-) mice is due to failure of endosomes containing reabsorbed proteins to fuse with lysosomes in the proximal tubule of the kidney. Failure of proteolysis is a novel mechanism for tubular proteinuria.
Assuntos
Nefropatias/genética , Rim/metabolismo , Proteínas de Membrana Lisossomal/genética , Proteinúria/genética , Receptores Depuradores/genética , Animais , Imunofluorescência , Humanos , Nefropatias/metabolismo , Proteína-2 Relacionada a Receptor de Lipoproteína de Baixa Densidade/metabolismo , Proteínas de Membrana Lisossomal/metabolismo , Lisossomos/metabolismo , Espectrometria de Massas , Camundongos , Camundongos Knockout , Proteinúria/metabolismo , Receptores Depuradores/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
OBJECTIVE: Mutations in SCARB2 were recently described as causing action myoclonus renal failure syndrome (AMRF). We hypothesized that mutations in SCARB2 might account for unsolved cases of progressive myoclonus epilepsy (PME) without renal impairment, especially those resembling Unverricht-Lundborg disease (ULD). Additionally, we searched for mutations in the PRICKLE1 gene, newly recognized as a cause of PME mimicking ULD. METHODS: We reviewed cases of PME referred for diagnosis over two decades in which a molecular diagnosis had not been reached. Patients were classified according to age of onset, clinical pattern, and associated neurological signs into "ULD-like" and "not ULD-like." After exclusion of mutations in cystatin B (CSTB), DNA was examined for sequence variation in SCARB2 and PRICKLE1. RESULTS: Of 71 cases evaluated, 41 were "ULD-like" and five had SCARB2 mutations. None of 30 "not ULD-like" cases were positive. The five patients with SCARB2 mutations had onset between 14 and 26 years of age, with no evidence of renal failure during 5.5 to 15 years of follow-up; four were followed until death. One living patient had slight proteinuria. A subset of 25 cases were sequenced for PRICKLE1 and no mutations were found. INTERPRETATION: Mutations in SCARB2 are an important cause of hitherto unsolved cases of PME resembling ULD at onset. SCARB2 should be evaluated even in the absence of renal involvement. Onset is in teenage or young adult life. Molecular diagnosis is important for counseling the patient and family, particularly as the prognosis is worse than classical ULD.
Assuntos
Proteínas de Membrana Lisossomal/genética , Mutação , Epilepsias Mioclônicas Progressivas/diagnóstico , Epilepsias Mioclônicas Progressivas/genética , Receptores Depuradores/genética , Insuficiência Renal/genética , Adolescente , Adulto , Diagnóstico Diferencial , Feminino , Seguimentos , Humanos , Masculino , Reação em Cadeia da Polimerase , Splicing de RNA , Insuficiência Renal/diagnóstico , Síndrome de Unverricht-Lundborg/diagnóstico , Síndrome de Unverricht-Lundborg/genética , Adulto JovemRESUMO
Benign familial neonatal convulsions (BFNC) is an autosomal dominant epilepsy of infancy, with loci mapped to human chromosomes 20q13.3 and 8q24. By positional cloning, a potassium channel gene (KCNQ2) located on 20q13.3 was isolated and found to be expressed in brain. Expression of KCNQ2 in frog (Xenopus laevis) oocytes led to potassium-selective currents that activated slowly with depolarization. In a large pedigree with BFNC, a five-base pair insertion would delete more than 300 amino acids from the KCNQ2 carboxyl terminus. Expression of the mutant channel did not yield measurable currents. Thus, impairment of potassium-dependent repolarization is likely to cause this age-specific epileptic syndrome.
Assuntos
Epilepsia/genética , Canais de Potássio de Abertura Dependente da Tensão da Membrana , Canais de Potássio/genética , Potenciais de Ação , Sequência de Aminoácidos , Animais , Encéfalo/metabolismo , Mapeamento Cromossômico , Cromossomos Humanos Par 20 , Clonagem Molecular , Epilepsia/metabolismo , Feminino , Mutação da Fase de Leitura , Humanos , Recém-Nascido , Canal de Potássio KCNQ2 , Masculino , Dados de Sequência Molecular , Mutagênese Insercional , Oócitos/metabolismo , Fases de Leitura Aberta , Linhagem , Potássio/metabolismo , Canais de Potássio/química , Canais de Potássio/metabolismo , Xenopus laevisRESUMO
While most women with epilepsy can expect a normal pregnancy outcome, epilepsy remains a significant contributor to both maternal and perinatal morbidity. Pre-pregnancy planning must address reliable contraception and optimisation of antiepileptic drug (AED) regimens to minimise teratogenic risk while maintaining seizure control. The most recent data from the AED registries regarding malformations is presented in this review, as is the limited data on the newer AEDs and studies linking neurocognitive outcomes to AED exposure. During pregnancy, important considerations include; therapeutic drug monitoring, surveillance for obstetric complications and vigilance for seizures during the intrapartum and postpartum period.
Assuntos
Anticonvulsivantes/uso terapêutico , Epilepsia/tratamento farmacológico , Complicações na Gravidez/tratamento farmacológico , Anormalidades Induzidas por Medicamentos/etiologia , Anticonvulsivantes/efeitos adversos , Feminino , Humanos , Cuidado Pós-Natal/métodos , Cuidado Pré-Concepcional/métodos , Gravidez , Efeitos Tardios da Exposição Pré-NatalRESUMO
Periventricular heterotopia (PH) involves dramatic malformations of the human cerebral cortex. Here we show that PH is closely linked to markers in distal Xq28 (maximal two-point lod score = 4.77 for F8C at theta = 0; maximal multipoint lod score = 5.37), so that affected females are obligatory mosaics for the mutation; that PH is lethal to at least some affected males; that PH malformations consist of well-differentiated cortical neurons filling the adult subependymal zone; and that individuals with PH are at high risk for epilepsy, though they have no other neurological or external stigmata. The PH gene may represent an important epilepsy susceptibility locus in addition to playing a key role in normal cortical development.
Assuntos
Encefalopatias/genética , Córtex Cerebral , Coristoma/genética , Epilepsia/genética , Cromossomo X , Aborto Habitual/genética , Adulto , Encefalopatias/patologia , Coristoma/patologia , Epilepsia/patologia , Epilepsia Generalizada/genética , Epilepsia Generalizada/patologia , Epilepsia do Lobo Temporal/genética , Epilepsia do Lobo Temporal/patologia , Feminino , Morte Fetal/genética , Genes Dominantes , Genes Letais , Humanos , Recém-Nascido , Escore Lod , Imageamento por Ressonância Magnética , Masculino , Linhagem , GravidezRESUMO
Long-range, directed migration is particularly dramatic in the cerebral cortex, where postmitotic neurons generated deep in the brain migrate to form layers with distinct form and function. In the X-linked dominant human disorder periventricular heterotopia (PH), many neurons fail to migrate and persist as nodules lining the ventricular surface. Females with PH present with epilepsy and other signs, including patent ductus arteriosus and coagulopathy, while hemizygous males die embryonically. We have identified the PH gene as filamin 1 (FLN1), which encodes an actin-cross-linking phosphoprotein that transduces ligand-receptor binding into actin reorganization, and which is required for locomotion of many cell types. FLN1 shows previously unrecognized, high-level expression in the developing cortex, is required for neuronal migration to the cortex, and is essential for embryogenesis.
Assuntos
Anormalidades Múltiplas/genética , Encefalopatias/genética , Encéfalo/patologia , Córtex Cerebral/fisiopatologia , Ventrículos Cerebrais , Coristoma/genética , Proteínas Contráteis/genética , Proteínas dos Microfilamentos/genética , Neurônios/fisiologia , Envelhecimento , Animais , Encéfalo/anormalidades , Encéfalo/anatomia & histologia , Encefalopatias/patologia , Encefalopatias/fisiopatologia , Córtex Cerebral/anormalidades , Córtex Cerebral/patologia , Ventrículos Cerebrais/anormalidades , Ventrículos Cerebrais/patologia , Coristoma/fisiopatologia , Mapeamento Cromossômico , Desenvolvimento Embrionário e Fetal , Epilepsia/genética , Feminino , Morte Fetal , Filaminas , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Imageamento por Ressonância Magnética , Masculino , Camundongos , Neurônios/patologia , Linhagem , Fenótipo , Caracteres Sexuais , Cromossomo XRESUMO
BACKGROUND: Benign familial neonatal seizures are most often caused by mutations in the voltage-gated potassium channel subunit gene KCNQ2. More than 60 mutations have been described in BFNS families, approximately half of which lead to protein truncation. The hypothesis of this study was that deletion or duplication of >or=1 exons of KCNQ2 could cause BFNS in cases without coding or splicing mutations. METHODS: Multiplex ligation-dependent probe amplification (MLPA) was used to test a group of 21 unrelated patients with clinical features consistent with either BFNS, benign familial neonatal-infantile seizures or sporadic neonatal seizures, for exonic deletions and duplications. RESULTS: Three deletions and one duplication mutation were identified in four familial cases and cascade testing of their available family members showed that the mutations segregated with the phenotype in each family. The junction fragment for one of the deletions was amplified by PCR and sequenced to characterise the breakpoint and verify that a deletion had occurred. CONCLUSIONS: Submicroscopic deletions or duplications of KCNQ2 are seen in a significant proportion of BFNS families: four of nine (44%) cases previously testing negative for coding or splice site mutation by sequencing KCNQ2 and KCNQ3. MLPA is an efficient second-tier testing strategy for KCNQ2 to identify pathogenic intragenic mutations not detectable by conventional DNA sequencing methods.
Assuntos
Epilepsia Neonatal Benigna/genética , Deleção de Genes , Duplicação Gênica , Canal de Potássio KCNQ2/genética , Adulto , Pré-Escolar , Análise Mutacional de DNA , Epilepsia/genética , Éxons/genética , Feminino , Humanos , Lactente , Recém-Nascido , Canal de Potássio KCNQ2/química , Canal de Potássio KCNQ2/deficiência , Masculino , Pessoa de Meia-Idade , Técnicas de Amplificação de Ácido Nucleico , Linhagem , Fenótipo , Reação em Cadeia da Polimerase/métodos , Análise de Sequência de DNARESUMO
Photosensitive seizures occur most commonly in childhood and adolescence, usually as a manifestation of complex idiopathic generalized epilepsies (IGEs). Molecular mechanisms underlying this condition are yet to be determined because no susceptibility genes have been identified. The NEDD4-2 (Neuronally Expressed Developmentally Downregulated 4) gene encodes a ubiquitin protein ligase proposed to regulate cell surface levels of several ion channels, receptors and transporters involved in regulating neuronal excitability, including voltage-gated sodium channels (VGSCs), the most clinically relevant of the epilepsy genes. The regulation of NEDD4-2 in vivo involves complex interactions with accessory proteins in a cell type specific manner. We screened NEDD4-2 for mutations in a cohort of 253 families with IGEs. We identified three NEDD4-2 missense changes in highly conserved residues; S233L, E271A and H515P in families with photosensitive generalized epilepsy. The NEDD4-2 variants were as effective as wild-type NEDD4-2 in downregulating the VGSC subtype Na(v)1.2 when assessed in the Xenopus oocyte heterologous expression system showing that the direct interaction with the ion channel was not altered by these variants. These data raise the possibility that photosensitive epilepsy may arise from defective interaction of NEDD4-2 with as yet unidentified accessory or target proteins.
Assuntos
Epilepsia Generalizada/genética , Epilepsia Reflexa/genética , Ativação do Canal Iônico/genética , Ubiquitina-Proteína Ligases/genética , Estudos de Casos e Controles , Cromossomos Humanos Par 18/genética , Estudos de Coortes , Complexos Endossomais de Distribuição Requeridos para Transporte , Epilepsia Generalizada/metabolismo , Epilepsia Reflexa/metabolismo , Feminino , Predisposição Genética para Doença , Humanos , Ativação do Canal Iônico/fisiologia , Masculino , Mutação de Sentido Incorreto , Ubiquitina-Proteína Ligases Nedd4 , Linhagem , Deleção de Sequência , Homologia de Sequência de Aminoácidos , Canais de Sódio/metabolismo , Proteínas de XenopusRESUMO
Two novel mutations (R85C and R85H) on the extracellular immunoglobulin-like domain of the sodium channel beta1 subunit have been identified in individuals from two families with generalized epilepsy with febrile seizures plus (GEFS+). The functional consequences of these two mutations were determined by co-expression of the human brain NaV1.2 alpha subunit with wild type or mutant beta1 subunits in human embryonic kidney (HEK)-293T cells. Patch clamp studies confirmed the regulatory role of beta1 in that relative to NaV1.2 alone the NaV1.2+beta1 currents had right-shifted voltage dependence of activation, fast and slow inactivation and reduced use dependence. In addition, the NaV1.2+beta1 current entered fast inactivation slightly faster than NaV1.2 channels alone. The beta1(R85C) subunit appears to be a complete loss of function in that none of the modulating effects of the wild type beta1 were observed when it was co-expressed with NaV1.2. Interestingly, the beta1(R85H) subunit also failed to modulate fast kinetics, however, it shifted the voltage dependence of steady state slow inactivation in the same way as the wild type beta1 subunit. Immunohistochemical studies revealed cell surface expression of the wild type beta1 subunit and undetectable levels of cell surface expression for both mutants. The functional studies suggest association of the beta1(R85H) subunit with the alpha subunit where its influence is limited to modulating steady state slow inactivation. In summary, the mutant beta1 subunits essentially fail to modulate alpha subunits which could increase neuronal excitability and underlie GEFS+ pathogenesis.
Assuntos
Química Encefálica/genética , Epilepsia Generalizada/genética , Predisposição Genética para Doença/genética , Mutação/genética , Convulsões Febris/genética , Canais de Sódio/genética , Potenciais de Ação/genética , Encéfalo/metabolismo , Encéfalo/fisiopatologia , Linhagem Celular , Epilepsia Generalizada/metabolismo , Epilepsia Generalizada/fisiopatologia , Humanos , Ativação do Canal Iônico/genética , Potenciais da Membrana/genética , Canal de Sódio Disparado por Voltagem NAV1.1 , Proteínas do Tecido Nervoso/genética , Técnicas de Patch-Clamp , Subunidades Proteicas/genética , Convulsões Febris/metabolismo , Convulsões Febris/fisiopatologia , Sinapses/genética , Sinapses/metabolismo , Transmissão Sináptica/genética , Transfecção , Subunidade beta-1 do Canal de Sódio Disparado por VoltagemRESUMO
1. Suspensions of avian erythroid nuclei, of high purity, were prepared. Acetylation of histones was observed when nuclei were incubated in the presence of [1-14C]acetyl CoA, but not in the presence of sodium [3H]acetate. 2. The acetylation reaction was very heat labile and reproduced the in vivo reaction with high fidelity. The reaction was strongly inhibited by divalent cations and cysteine. 3. Studies, in which intact cells were pre-incubated with cycloheximide prior to the isolation of nuclei, suggested that histone acetylation in isolated erythroid nuclei was largely independent of histone synthesis. 4. The pH profile suggested the presence of at least two histone acetyltransferases, with pH optima at 8.0 and 8.6. Acetylation of histone H4 appeared to be favoured at pH 8.0. 5. Studies on histone acetylation in isolated nuclei should be very useful in correlating observations on histone acetylation in vivo, with experiments using purified histone acetyltransferases.
Assuntos
Acetiltransferases/sangue , Núcleo Celular/metabolismo , Eritrócitos/metabolismo , Histonas/sangue , Animais , Cálcio/farmacologia , Núcleo Celular/efeitos dos fármacos , Galinhas , Cicloeximida/farmacologia , Concentração de Íons de Hidrogênio , Cinética , Magnésio/farmacologia , Manganês/farmacologia , Potássio/farmacologiaRESUMO
Juvenile neuronal-ceroid-lipofuscinosis (JNCL) is a lysosomal storage disease caused by mutations in CLN3. The most frequent mutation is a 1.02-kb deletion that, when homozygous, causes the classical clinical presentation. Patients harboring mutations different than the major deletion show a marked clinical heterogeneity, including protracted disease course with possible involvement of extraneuronal tissues. Cardiac involvement is relatively rare in JNCL and it is usually due to myocardial storage of ceroid-lipofuscinin. Only recently, histopathological findings of autophagic vacuolar myopathy (AVM) were detected in JNCL patients with severe cardiomyopathy. We describe a 35-year-old male showing a delayed-classic JNCL with visual loss in childhood and neurological manifestations only appearing in adult life. He had an unusual CLN3 genotype with an unreported deletion (p.Ala349_Leu350del) and the known p.His315Glnfs*67 mutation. Autophagic vacuolar myopathy was shown by muscle biopsy. At clinical follow-up, moderately increased CPK levels were detected whereas periodic cardiac assessments have been normal to date. Adult neurologists should be aware of protracted JNCL as cause of progressive neurological decline in adults. The occurrence of autophagic vacuolar myopathy necessitates periodic cardiac surveillance, which is not usually an issue in classic JNCL due to early neurological death.
Assuntos
Deleção de Genes , Doenças por Armazenamento dos Lisossomos/genética , Glicoproteínas de Membrana/genética , Chaperonas Moleculares/genética , Doenças Musculares/genética , Lipofuscinoses Ceroides Neuronais/genética , Adulto , Humanos , Doenças por Armazenamento dos Lisossomos/diagnóstico , Masculino , Doenças Musculares/diagnóstico , Lipofuscinoses Ceroides Neuronais/diagnóstico , SíndromeRESUMO
Three unrelated patients, aged 4, 18, and 47 years, had generalized dystonia associated with bilateral striatal hypodensities on computed tomography. Mitochondrial encephalopathy was considered to be the most likely diagnosis, but this could not be proved. These patients confirm previous reports linking acquired generalized dystonia with bilateral putaminal lesions and they highlight the problem in differential diagnosis of this clinicoradiologic syndrome.
Assuntos
Encefalopatias/complicações , Distonia/complicações , Putamen , Adolescente , Encéfalo/ultraestrutura , Encefalopatias/diagnóstico por imagem , Pré-Escolar , Distonia/diagnóstico por imagem , Humanos , Doença de Leigh/complicações , Masculino , Pessoa de Meia-Idade , Mitocôndrias/ultraestrutura , Putamen/diagnóstico por imagem , Tomografia Computadorizada por Raios XRESUMO
One hundred consecutive cases of clinically diagnosed, acute forebrain infarction were studied using computerized tomography (CT) and electroencephalography (EEG). Computed tomography confirmed brain infarction in 91 patients and was normal in the remaining nine. Each EEG was read independently by two experienced electroencephalographers without knowledge of CT or clinical details and their findings were compared with those of CT. Lateralized theta and/or delta activity predicted ipsilateral cortical infarction with a sensitivity of 76% and specificity of 82%. In contrast, cerebral hemisphere lacunae produced similar EEG abnormalities in only a few cases (9%). Electroencephalography is particularly useful following stroke if the initial CT excludes hemorrhage but does not detect infarction. In conjunction with clinical details, the EEG can then be used to indicate the likelihood of cortical involvement and thus suggest the likely pathophysiologic mechanism of infarction.