Confirming an expanded spectrum of SCN2A mutations: a case series.

Mutations in sodium channel genes are highly associated with epilepsy. Mutation of SCN1A, the gene encoding the voltage gated sodium channel (VGSC) alpha subunit type 1 (Nav1.1), causes Dravet syndrome spectrum disorders.

Re-evaluation of PRRT2 mutations in paroxysmal disorders.

Mutations in PRRT2 have recently been identified as the major cause of autosomal dominant benign familial infantile epilepsy (BFIE), infantile convulsions with choreoathetosis syndrome (ICCA), and paroxysmal kinesigenic dyskinesia (PKD). Other paroxysmal disorders like febrile seizures, migraine, paroxysmal exercise-induced dyskinesia, and paroxysmal non-kinesigenic dyskinesia have also been shown to be associated with this gene. We re-evaluated PRRT2 mutations and genetic-clinical correlations in additional cases with PKD/ICCA and other paroxysmal disorders.

SLC25A22 is a novel gene for migrating partial seizures in infancy.

Objective: To identify a genetic cause for migrating partial seizures in infancy (MPSI).

Methods: We characterized a consanguineous pedigree with MPSI and obtained DNA from affected and unaffected family members. We analyzed single nucleotide polymorphism 500K data to identify regions with evidence of linkage.

The kick-in system: a novel rapid knock-in strategy.

Knock-in mouse models have contributed tremendously to our understanding of human disorders. However, generation of knock-in animals requires a significant investment of time and effort. We addressed this problem by developing a novel knock-in system that circumvents several traditional challenges by establishing stem cells with acceptor elements enveloping a particular genomic target.

Kcnq1-5 (Kv7.1-5) potassium channel expression in the adult zebrafish.

Background: KCNQx genes encode slowly activating-inactivating K+ channels, are linked to physiological signal transduction pathways, and mutations in them underlie diseases such as long QT syndrome (KCNQ1), epilepsy in adults (KCNQ2/3), benign familial neonatal convulsions in children (KCNQ3), and hearing loss or tinnitus in humans (KCNQ4, but not KCNQ5). Identification of kcnqx potassium channel transcripts in zebrafish (Danio rerio) remains to be fully characterized although some genes have been mapped to the genome. Using zebrafish genome resources as the source of putative kcnq sequences, we investigated the expression of kcnq1-5 in heart, brain and ear tissues.

Sodium channels, inherited epilepsy, and antiepileptic drugs.

Voltage-gated sodium channels initiate action potentials in brain neurons, mutations in sodium channels cause inherited forms of epilepsy, and sodium channel blockers-along with other classes of drugs-are used in therapy of epilepsy. A mammalian voltage-gated sodium channel is a complex containing a large, pore-forming α subunit and one or two smaller β subunits. Extensive structure-function studies have revealed many aspects of the molecular basis for sodium channel structure, and X-ray crystallography of ancestral bacterial sodium channels has given insight into their three-dimensional structure.

KCNQ2 encephalopathy: delineation of the electroclinical phenotype and treatment response.

Neonatal-onset epilepsies are rare conditions, mostly genetically determined, that can have a benign or severe phenotype.(1,2) There is recent recognition of de novo KCNQ2 mutations in patients with severe neonatal-onset epilepsy with intractable seizures and severe psychomotor impairment, termed KCNQ2 encephalopathy.(3,4) This is a rare condition and all patients reported so far were diagnosed well after the neonatal period.

Phenotypes and PRRT2 mutations in Chinese families with benign familial infantile epilepsy and infantile convulsions with paroxysmal choreoathetosis.

Background: Mutations in the PRRT2 gene have been identified as the major cause of benign familial infantile epilepsy (BFIE), paroxysmal kinesigenic dyskinesia (PKD) and infantile convulsions with paroxysmal choreoathetosis/dyskinesias (ICCA). Here, we analyzed the phenotypes and PRRT2 mutations in Chinese families with BFIE and ICCA.

Methods: Clinical data were collected from 22 families with BFIE and eight families with ICCA.

Calmodulin orchestrates the heteromeric assembly and the trafficking of KCNQ2/3 (Kv7.2/3) channels in neurons.

Mutations in KCNQ2 and KCNQ3 genes are responsible for benign familial neonatal seizures and epileptic encephalopathies. Some of these mutations have been shown to alter the binding of calmodulin (CaM) to specific C-terminal motifs of KCNQ subunits, known as the A and B helices. Here, we show that the mutation I342A in the A helix of KCNQ3 abolishes CaM interaction and strongly decreases the heteromeric association with KCNQ2.

Dominant-negative effects of KCNQ2 mutations are associated with epileptic encephalopathy.

Objective: Mutations in KCNQ2 and KCNQ3, encoding the voltage-gated potassium channels KV 7.2 and KV 7.3, are known to cause benign familial neonatal seizures mainly by haploinsufficiency.

Benign infantile convulsions (IC) and subsequent paroxysmal kinesigenic dyskinesia (PKD) in a patient with 16p11.2 microdeletion syndrome.

Paroxysmal kinesigenic dyskinesia with infantile convulsions (PKD/IC) is caused by mutations in the gene PRRT2 located in 16p11.2. A deletion syndrome 16p11.

[Differential diagnoses of West syndrome].

This study describes the clinical and electroencephalographic characteristics of epileptic spasms, and more especially those that occur during the first two years of life (infantile spasms). West syndrome has been clearly defined as the association between infantile spasms with an electroencephalographic pattern of hypsarrhythmia. Although intellectual deficit appears in almost all cases in which infantile spasms are not controlled with medication, this is a developmental aspect of the condition and not a manifestation that must necessarily be present in order to define the syndrome.

Mutation analysis of PRRT2 in two Chinese BFIS families and nomenclature of PRRT2 related paroxysmal diseases.

Benign familial infantile seizure (BFIS) and paroxysmal kinesigenic dyskinesia (PKD) are autosomal-dominant inherited self-limited neurological disorders. BFIS is characterized by clusters of epileptic seizures in infancy while, in some cases, infantile seizures and adolescent-onset paroxysmal kinesigenic choreoathetosis co-occurred, which is called infantile convulsions and choreoathetosis (ICCA) syndrome. We and other researchers have reported the proline-rich transmembrane protein 2 (PRRT2) as the causative gene of PKD.

Epilepsy in children with periventricular leukomalacia.

Objective: We aimed to analyze the development of epilepsy in a patient group with periventricular leukomalacia followed at a tertiary pediatric neurology center.

Patients And Methods: The study included 108 children aged between 2 and 8 years with radiologically proven periventricular leukomalacia who had been regularly observed at the Istanbul University, Istanbul Faculty of Medicine, Department of Pediatrics, Pediatric Neurology outpatient clinic between January 2006 and December 2011.

Results: Neonatal seizures were reported in 22 patients (20.

An SCN2A mutation in a family with infantile seizures from Madagascar reveals an increased subthreshold Na(+) current.

Missense mutations in SCN2A, encoding the brain sodium channel NaV 1.2, have been described in benign familial neonatal-infantile seizures (BFNIS), a self-limiting disorder, whereas several SCN2A de novo nonsense mutations have been found in patients with more severe phenotypes including epileptic encephalopathy. We report a family with BFNIS originating from Madagascar.

Similar early characteristics but variable neurological outcome of patients with a de novo mutation of KCNQ2.

Background: Early onset epileptic encephalopathies (EOEEs) are dramatic heterogeneous conditions in which aetiology, seizures and/or interictal EEG have a negative impact on neurological development. Several genes have been associated with EOEE and a molecular diagnosis workup is challenging since similar phenotypes are associated with mutations in different genes and since mutations in one given gene can be associated with very different phenotypes. Recently, de novo mutations in KCNQ2, have been found in about 10% of EOEE patients.

Differential diagnosis of epileptic seizures in infancy including the neonatal period.

It is important to accurately diagnose epileptic seizures in early life to optimise management and prognosis. Conversely, however, many different movements and behaviours may manifest in the neonatal period and infancy that may not have at their root cause a change in electrical activity of the brain. It is important to distinguish them from epileptic seizures to avoid over- and inappropriate treatment.

Nonepileptic paroxysmal sleep disorders.

Events occurring during nighttime sleep in children can be easily mislabeled, as witnesses are usually not immediately available. Even when observers are present, description of the events can be sketchy, as these individuals are frequently aroused from their own sleep. Errors of perception are thus common and can lead to diagnosis of epilepsy where other sleep-related conditions are present, sometimes initiating unnecessary therapeutic interventions, especially with antiepileptic drugs.

Idiopathic focal epilepsies.

In this chapter we include a series of epilepsies with onset in pediatric age characterized by focal seizures, idiopathic etiology, normal psychomotor development, and a benign course related to the spontaneous remission of seizures without sequelae. These entities are age-dependent and seizures tend to disappear spontaneously. For these reasons often the drug treatment is not necessary.

Neonatal seizures.

Epileptic seizures are more frequent in the neonate than at any other time. The incidence of neonatal seizures (NNS) is estimated to be between 1.5 and 5.

Brain maturation and epilepsy.

At full term, both glutamate and gamma-amino-butyric acid (GABA) are excitatory; cortical synapses are beginning to appear, there is little myelin in the cerebral hemispheres, and long tracts hardly start to develop. Neonatal myoclonic encephalopathy can result from premature activation of N-methyl-D-aspartate (NMDA) transmission. Benign neonatal seizures and migrating partial seizures in infancy could involve excessive or premature excitability of deep cortical layers.