Exome Sequencing and the Identification of New Genes and Shared Mechanisms in Polymicrogyria.

Importance: Polymicrogyria is the most commonly diagnosed cortical malformation and is associated with neurodevelopmental sequelae including epilepsy, motor abnormalities, and cognitive deficits. Polymicrogyria frequently co-occurs with other brain malformations or as part of syndromic diseases. Past studies of polymicrogyria have defined heterogeneous genetic and nongenetic causes but have explained only a small fraction of cases.

Progressive myoclonus epilepsies-Residual unsolved cases have marked genetic heterogeneity including dolichol-dependent protein glycosylation pathway genes.

Progressive myoclonus epilepsies (PMEs) comprise a group of clinically and genetically heterogeneous rare diseases. Over 70% of PME cases can now be molecularly solved. Known PME genes encode a variety of proteins, many involved in lysosomal and endosomal function.

Comparative analysis of the safety and tolerability of eslicarbazepine acetate in older (≥60 years) and younger (18-59 years) adults.

Objective: To investigate the safety and tolerability of eslicarbazepine acetate (ESL), a once-daily oral anti-seizure drug (ASD), in older and younger adult patient populations.

Methods: Two post-hoc pooled data analyses were performed: one from three Phase III studies in patients with focal (partial-onset) seizures who were taking 1-3 concomitant ASDs; the other from five Phase II studies in patients from non-epilepsy populations not taking other ASDs chronically and/or at a clinically-effective anti-seizure dose. The frequencies of treatment-emergent adverse events (TEAEs) were calculated for the older (≥60 years) and younger (18-59 years) adults separately.

Autosomal-dominant adult neuronal ceroid lipofuscinosis caused by duplication in DNAJC5 initially missed by Sanger and whole-exome sequencing.

Adult-onset neuronal ceroid lipofuscinoses (ANCL, Kufs disease) are rare hereditary neuropsychiatric disorders characterized by intralysosomal accumulation of ceroid in tissues. The ceroid accumulation primarily affects the brain, leading to neuronal loss and progressive neurodegeneration. Although several causative genes have been identified (DNAJC5, CLN6, CTSF, GRN, CLN1, CLN5, ATP13A2), the genetic underpinnings of ANCL in some families remain unknown.

Duplication 2p16 is associated with perisylvian polymicrogyria.

Polymicrogyria (PMG) is a heterogeneous brain malformation that may result from prenatal vascular disruption or infection, or from numerous genetic causes that still remain difficult to identify. We identified three unrelated patients with polymicrogyria and duplications of chromosome 2p, defined the smallest region of overlap, and performed gene pathway analysis using Cytoscape. The smallest region of overlap in all three children involved 2p16.

Kufs disease due to mutation of CLN6: clinical, pathological and molecular genetic features.

Kufs disease is the major adult form of neuronal ceroid lipofuscinosis, but is rare and difficult to diagnose. Diagnosis was traditionally dependent on the demonstration of characteristic storage material, but distinction from normal age-related accumulation of lipofuscin can be challenging. Mutation of CLN6 has emerged as the most important cause of recessive Kufs disease but, remarkably, is also responsible for variant late infantile ceroid lipofuscinosis.

Sodium Channel SCN3A (Na1.3) Regulation of Human Cerebral Cortical Folding and Oral Motor Development.

Channelopathies are disorders caused by abnormal ion channel function in differentiated excitable tissues. We discovered a unique neurodevelopmental channelopathy resulting from pathogenic variants in SCN3A, a gene encoding the voltage-gated sodium channel Na1.3.

Evidence of linkage to chromosome 5p13.2-q11.1 in a large inbred family with genetic generalized epilepsy.

The clinical genetics of genetic generalized epilepsy suggests complex inheritance; large pedigrees, with multiple affected individuals, are rare exceptions. We studied a large consanguineous family from Turkey where extensive electroclinical phenotyping revealed a familial phenotype most closely resembling juvenile myoclonic epilepsy. For a subject to be considered affected (n = 14), a diagnostic electroencephalogram was required.

Psychiatric and cognitive adverse events: A pooled analysis of three phase III trials of adjunctive eslicarbazepine acetate for partial-onset seizures.

Objective: To evaluate the nature and incidence of psychiatric and cognitive adverse events (AEs) reported with eslicarbazepine acetate (ESL) used as adjunctive treatment for refractory partial-onset seizures (POS) in adults.

Methods: This was a post-hoc analysis of data pooled from three randomized double-blind, placebo-controlled trials (BIA-2093-301, -302, -304). After an 8-week baseline period, patients received placebo or adjunctive ESL 400mg (studies 301 and 302 only), 800mg, or 1200mg once daily (QD) for 14weeks (2-week titration period, 12-week maintenance period).

Myoclonus epilepsy and ataxia due to KCNC1 mutation: Analysis of 20 cases and K channel properties.

Objective: To comprehensively describe the new syndrome of myoclonus epilepsy and ataxia due to potassium channel mutation (MEAK), including cellular electrophysiological characterization of observed clinical improvement with fever.

Methods: We analyzed clinical, electroclinical, and neuroimaging data for 20 patients with MEAK due to recurrent KCNC1 p.R320H mutation.

Research conference summary from the 2014 International Task Force on -Related Disorders.

Objective: -related neurologic disorders encompass a broad range of phenotypes that extend well beyond initial phenotypic criteria associated with alternating hemiplegia of childhood (AHC) and rapid-onset dystonia parkinsonism.

Methods: In 2014, the Alternating Hemiplegia of Childhood Foundation hosted a multidisciplinary workshop intended to address fundamental challenges surrounding the diagnosis and management of individuals with -related disorders.

Results: Workshop attendees were charged with the following: (1) to achieve consensus on expanded diagnostic criteria to facilitate the identification of additional patients, intended to supplement existing syndrome-specific diagnostic paradigms; (2) to standardize definitions for the broad range of paroxysmal manifestations associated with AHC to disseminate to families; (3) to create clinical recommendations for common recurrent issues facing families and medical care providers; (4) to review data related to the death of individuals in the Alternating Hemiplegia of Childhood Foundation database to guide future efforts in identifying at-risk subjects and potential preventative measures; and (5) to identify critical gaps where we most need to focus national and international research efforts.

Myoclonus and seizures in progressive myoclonus epilepsies: pharmacology and therapeutic trials.

Generalized motor seizures, usually tonic-clonic, tonic-vibratory, myoclonic or clonic, and stimulus-sensitive/action myoclonus are typical features of progressive myoclonus epilepsies (PMEs). Despite the introduction of many anticonvulsants, the treatment of these symptoms, particularly myoclonus, remains challenging, due to the incomplete and often transitory effects of most drugs. Moreover, treatment is only symptomatic, since therapy targeting the underlying aetiology for these genetic conditions is in its infancy.

Brivaracetam in Unverricht-Lundborg disease (EPM1): Results from two randomized, double-blind, placebo-controlled studies.

Objective: To evaluate efficacy, tolerability, and safety of adjunctive brivaracetam (BRV) in patients with Unverricht-Lundborg disease (EPM1).

Methods: Two prospective, multicenter, double-blind, phase III trials (N01187/NCT00357669; N01236/NCT00368251) in patients (≥16 years) with genetically ascertained EPM1, showing moderate-severe myoclonus (action myoclonus score ≥30/160), randomized (1:1:1) to twice-daily BRV (N01187: 50 or 150 mg/day; N01236: 5 or 150 mg/day), or placebo. Both studies comprised a baseline period (2 weeks), 2-week up-titration period, 12-week stable-dose maintenance period, and down-titration or entry into long-term follow-up study.

The histopathology of polymicrogyria: a series of 71 brain autopsy studies.

Aim: Polymicrogyria (PMG) is one of the most common forms of cortical malformation yet the mechanism of its development remains unknown. This study describes the histopathological aspects of PMG in a large series including a significant proportion of fetal cases.

Method: We have reviewed the neuropathology and medical records of 44 fetuses and 27 children and adults in whom the cortical architecture was focally or diffusely replaced by one or more festooning bands of neurons.

Alternating Hemiplegia of Childhood: Retrospective Genetic Study and Genotype-Phenotype Correlations in 187 Subjects from the US AHCF Registry.

Mutations in ATP1A3 cause Alternating Hemiplegia of Childhood (AHC) by disrupting function of the neuronal Na+/K+ ATPase. Published studies to date indicate 2 recurrent mutations, D801N and E815K, and a more severe phenotype in the E815K cohort. We performed mutation analysis and retrospective genotype-phenotype correlations in all eligible patients with AHC enrolled in the US AHC Foundation registry from 1997-2012.

Familial focal epilepsy with focal cortical dysplasia due to DEPDC5 mutations.

Objective: The DEPDC5 (DEP domain-containing protein 5) gene, encoding a repressor of the mTORC1 signaling pathway, has recently emerged as a major gene mutated in familial focal epilepsies. We aimed to further extend the role of DEPDC5 to focal cortical dysplasias (FCDs).

Methods: Seven patients from 4 families with DEPDC5 mutations and focal epilepsy associated with FCD were recruited and investigated at the clinical, neuroimaging, and histopathological levels.

A recurrent de novo mutation in KCNC1 causes progressive myoclonus epilepsy.

Progressive myoclonus epilepsies (PMEs) are a group of rare, inherited disorders manifesting with action myoclonus, tonic-clonic seizures and ataxia. We sequenced the exomes of 84 unrelated individuals with PME of unknown cause and molecularly solved 26 cases (31%). Remarkably, a recurrent de novo mutation, c.

Rasmussen encephalitis and comorbid autoimmune diseases: A window into disease mechanism?

Objective: To describe a potential association between comorbid autoimmune disease and Rasmussen encephalitis (RE) and discuss potential insights into underlying RE pathogenesis.

Methods: We report a case series of 4 patients with RE in whom a comorbid autoimmune disease was subsequently diagnosed and review the literature on possible common susceptibility factors.

Results: In 4 patients who presented with typical clinical features of RE, a comorbid autoimmune disease was subsequently diagnosed: Hashimoto thyroiditis, ulcerative colitis, Crohn disease, and systemic lupus erythematosus.

Somatic mutations in cerebral cortical malformations.

Background: Although there is increasing recognition of the role of somatic mutations in genetic disorders, the prevalence of somatic mutations in neurodevelopmental disease and the optimal techniques to detect somatic mosaicism have not been systematically evaluated.

Methods: Using a customized panel of known and candidate genes associated with brain malformations, we applied targeted high-coverage sequencing (depth, ≥200×) to leukocyte-derived DNA samples from 158 persons with brain malformations, including the double-cortex syndrome (subcortical band heterotopia, 30 persons), polymicrogyria with megalencephaly (20), periventricular nodular heterotopia (61), and pachygyria (47). We validated candidate mutations with the use of Sanger sequencing and, for variants present at unequal read depths, subcloning followed by colony sequencing.

A new locus for familial temporal lobe epilepsy on chromosome 3q.

Background: Temporal lobe epilepsy (TLE) is a common and heterogeneous focal epilepsy syndrome with a complex etiology, involving both environmental and genetic factors. Several familial forms of TLE have been described, including familial lateral TLE (FLTLE), familial mesial TLE (FMTLE) without hippocampal sclerosis, and FMTLE with hippocampal sclerosis. Mutations have been identified only in the leucine-rich, glioma-inactivated 1 (LGI1) gene on chromosome 10q22-q24 in FLTLE.

Role of the sodium channel SCN9A in genetic epilepsy with febrile seizures plus and Dravet syndrome.

Mutations of the SCN1A subunit of the sodium channel is a cause of genetic epilepsy with febrile seizures plus (GEFS(+) ) in multiplex families and accounts for 70-80% of Dravet syndrome (DS). DS cases without SCN1A mutation inherited have predicted SCN9A susceptibility variants, which may contribute to complex inheritance for these unexplained cases of DS. Compared with controls, DS cases were significantly enriched for rare SCN9A genetic variants.

SCN1A testing for epilepsy: application in clinical practice.

This report is a practical reference guide for genetic testing of SCN1A, the gene encoding the α1 subunit of neuronal voltage-gated sodium channels (protein name: Nav 1.1). Mutations in this gene are frequently found in Dravet syndrome (DS), and are sometimes found in genetic epilepsy with febrile seizures plus (GEFS+), migrating partial seizures of infancy (MPSI), other infantile epileptic encephalopathies, and rarely in infantile spasms.

Mutations in DEPDC5 cause familial focal epilepsy with variable foci.

The majority of epilepsies are focal in origin, with seizures emanating from one brain region. Although focal epilepsies often arise from structural brain lesions, many affected individuals have normal brain imaging. The etiology is unknown in the majority of individuals, although genetic factors are increasingly recognized.