SCN2A mutation in an infant with Ohtahara syndrome and neuroimaging findings: expanding the phenotype of neuronal migration disorders

Neuronal migration disorders (NMDs) are a heterogeneous group of conditions caused by the abnormal migration of neuroblasts in the developing brain and nervous system, resulting in severe developmental impairment, intractable epilepsy and intellectual disability (Spalice et al. 2009). To date, many genes have been identified as the leading cause of migration defects, i.e. agyria/pachygyria, polymicrogyria, heterotopias, agenesis of the corpus callosum and agenesis of the cranial nerves (Spalice et al. 2009). Here, we present a patient with early infantile epileptic encephalopathy (Ohtahara syndrome) with seizure onset on the first dayof life, severe developmental delay and an abnormal brain MRI with excessive folding of small, fused gyri and bilateral perisylvian polymicrogyria, suggestive of neuronal migration disorder. To clarify the unknown aetiology, we conducted whole-exome sequencing, which detected a de novo missense variant (c.5308A>T; p.(Met1770Leu)) in the SCN2A gene. This is a report of SCN2A gene variant identified in a patient with neuronal migration disorder which could further expand the phenotypic spectrum of these genetic disorders.

Clinical Characteristics and Efficacy Analysis of Children with Cerebral Palsy and Neuronal Migration Disorders / 中国康复理论与实践

@#Objective To discuss the clinical characteristics and efficacy analysis of children with cerebral palsy and neuronal migration disorders (NMD) by retrospective analysis. Methods From June, 2005 to June, 2015, 32 children with cerebral palsy and NMD were en-rolled as NMD group, while 60 children with cerebral palsy with periventricular leukomalacia (PVL) as PVL group. Both groups received comprehensive rehabilitation for three months. Their clinical classification, complications of epilepsy or epileptiform discharges, the score of Gross Motor Function Measure (GMFM), and development quotient (DQ) were compared, as well as the follow-up results of six months. Results There was significant difference in the clinical classification of cerebral palsy between two groups (χ2=24.529, P<0.001). The inci-dence of epilepsy and epileptiform discharges was higher in NMD group than in PVL group (χ2>4.605, P<0.05). After treatment, the score of GMFM improved with time in both groups (Ftime=6.850, P=0.010), and was significantly lower in NMD group than in GMFM group (Fgroup=29.885, P<0.001);the scores of DQ in all the functional areas improved with time in both groups (Ftime>25.041, P<0.001), and were signifi-cantly lower in NMD group than in GMFM group (Fgroup>32.347, P<0.001). Conclusion Children with cerebral palsy and NMD are charac-terized by mental retardation, epilepsy and spastic hemiplegia, and poor outcome.

Heterotopía nodular periventricular, objetivo quirúrgico en epilepsia refractaria al manejo farmacológico / Periventricular Nodular Heterotopia, Surgical Goal in Drug-Resistant Epilepsy / Heterotopia Nodular Periventricular, objetivo cirúrgico em epilepsia refratária ao manejo farmacológico

Introducción: La heterotopía neuronal es un defecto de la migración en el cual estas células no completan su desplazamiento hacia la corteza. La forma más comúnmente reportada es la heterotopía nodular periventricular, caracterizada por conglomerados neuronales que se ubican adyacentes a las paredes de los ventrículos laterales. Hasta el 90% de los pacientes con esta condición presentan epilepsia en algún momento de la vida y una gran proporción de ellos serán refractarios al manejo farmacológico. Esto hace necesario un adecuado abordaje diagnóstico que busque establecer qué pacientes se beneficiarían de resección quirúrgica de la lesión, que en la mayoría de los casos ofrece una alta tasa de control de crisis. Desarrollo: Se presenta un recorrido desde la práctica por los aspectos con mayor relevancia en cuanto a la fisiopatología, manifestaciones clínicas, abordaje diagnóstico y terapéutico de la heterotopía nodular periventricular, con el fin de explorar el rol de esta condición como causante de epilepsia refractaria. Conclusión: La epilepsia refractaria al tratamiento condiciona de manera significativa la calidad de vida de los pacientes. Una entidad frecuentemente asociada a esto es la heterotopía nodular periventricular, la cual debe ser correctamente abordada por el equipo médico tratante procurando un diagnóstico oportuno y definiendo qué pacientes se benefician del manejo quirúrgico. De esta manera, se impacta positivamente la calidad de vida de estos sujetos y de sus cuidadores.

Introduction: Neuronal heterotopia is a migration disorder in which these cells do not complete their movement toward the cerebral cortex. Periventricular nodular heterotopia is the most frequently reported form, characterized by neuronal conglomerates adjacent to the lateral ventricles walls.About 90 % of patients with this condition suffer epilepsy at some point in their lives and the major proportion of them will be resistant to pharmacologic treatment. This makes an appropriate diagnostic approach necessary in order to determine which patients would benefit from surgical resection of the lesion, which in most cases offers a high rate of crisis control. Development: This article presents a review of the most important topics approached from the practice of periventricular nodular heterotopia pathophysiology, clinical features, diagnosis and therapy. It is aimed at exploring the role of this condition as a cause of intractable epilepsy. Conclusion: Pharmacologic treatment for resistant epilepsy will have a severe impact on patient's quality of life. Periventricular nodular heterotopia is frequently associated to this condition, which must be successfully approached by the medical team attempting to an opportune diagnosis and defining which patients would benefit from surgical management. This positively impacts the quality of life of these patients and their caregivers.

Introdução: A heterotopia neuronal é um defeito da migração no qual estas células não completam seu deslocamento ao córtex. A forma mais comunmente reportada é a heterotopia nodular periventricular, caracterizada por conglomerados neuronais que se localizam adjacentes às paredes dos ventrículos laterais. Até o 90% dos pacientes com esta condição apresentam epilepsia em algum momento da vida e uma grande proporção deles, serão refratários ao manejo farmacológico. Isto faz necessária uma adequada abordagem diagnóstica, buscando estabelecer quais pacientes se beneficiariam de ressecção cirúrgica da lesão, que na maioria dos casos oferece uma alta taxa de controle de crises. Desenvolvimento: Se apresenta um recorrido desde a prática pelos aspectos com maior relevância em quanto à fisiopatologia, manifestações clínicas, abordagem diagnóstica e terapêutica da heterotopia nodular periventricular. Com o fim de explorar o rol desta condição como causador de epilepsia refratária. Conclusão: A epilepsia refratária ao tratamento condiciona de maneira significativa à qualidade de vida dos pacientes. Uma entidade frequentemente associada a isto é a heterotopia nodular periventricular, a qual deve ser corretamente abordada pela equipe médica tratante procurando um diagnóstico oportuno e definindo quais pacientes se beneficiam de manejo cirúrgico. Desta forma impacta-se positivamente a qualidade de vida destes sujeitos e de seus cuidadores.

Bilateral Frontal Polymicrogyria: An Autopsy Case Report

Bilateral frontal polymicrogyria is a recently recognized syndrome characterized by symmetric polymicrogyria of both frontal lobes that presents with delayed motor and language development, spastic quadriparesis, and variable mental retardation. However, the postmortem findings of this syndrome are not fully elaborated. Here we describe an autopsy case of bilateral frontal polymicrogyria in a male fetus delivered at 22 weeks gestation due to extensive chorioamnionitis. The microscopic findings included a thinned cortical plate with fair neuronal maturation. There were no signs of neuronal damage and the white matter was unremarkable.

Malformations of cortical development / Malformações do desenvolvimento cortical

Malformations of cortical development (MCD) have been increasingly identified. The purpose of this presentation is to review the current knowledge of the MCD. Before we address this issue, we will briefly present a review of cortical development. The second part of this presentation will address the most important MCD. Finally, the last part of this presentation will address the correlation between MCD and epilepsy.

As malformações do desenvolvimento cortical (MDC) são cada vez mais identificadas e diagnosticadas. O propósito desta apresentação é rever o conhecimento recente sobre as MDC. Antes de abordarmos o assunto em questão, apresentaremos brevemente uma revisão sobre a formação cortical. A seguir, abordaremos as principais entidades compreendidas dentro da classificação das MDC e, finalmente, resumiremos a correlação entre MDC e epilepsia.

Kinetics of GABAa Receptors in An Animal Model of Irradiation-induced Neuronal Migration Disorders

PURPOSE: A majority of patients with neuronal migration disorders(NMDs) in cortical structures suffer from medically intractable epilepsy. The role of NMDs on seizure susceptibility or epileptogenecity has not been well documented. In the present study, we established an experimental model of NMDs in Sprague-Dawley rats by exposing fetal rats to external irradiation in order to demonstrate epileptogenic effect of NMDs lesions. METHODS: Pregnant rats were exposed to 240cGy of external X-irradiation delivered by a linear accelerator source on gestational day 16 and 17 to produce NMDs lesions in rat brain. RESULTS: Microcephaly was evident on gross examination of the affected brains. Seizure susceptibility was tested by a small dose of kainate(0.1mg/kg) injected intraperitoneally, and the irradiated animals showed increased susceptibility to kainate. Histopathologic examination revealed cortical dysplasia consisting of dyslamination of cerebral cortex and appearance of cytomegalic neurons, neuronal heterotopia in periventricular white matter, dispersion of pyramidal layer and hippocampal dentate gyrus, and agenesis of corpus callosum. Histopathologic change of the cerebral cortex and hippocampus was closely correlated with seizure activity. Quantitative autoradiography of [H]muscimol binding to GABAA receptors was significantly reduced in NMDs lesions(P=0.02). CONCLUSION: In utero irradiation of fetal rats resulted in histopathologic abnormalities that mi- miced several characteristic features of human neuronal migration disorders, and hyperexcitability appears to be associated with reduction in density of GABAp receptors in the brain, particularly in hippocampus and neocortex.

A Case of Neuronal Heterotopia

Neuronal migrational disorders of the brain represent abnormalities in the formation of the neocortex caused by faulty migration of the subependymal neuroblasts. The neuroblasts normally migrate between the sixth and 15th gestational week and in doing so form the six-layered neocortex. When the migration does not occur in a normal fashion the resultant brain anomalies include lissencephaly, pachygyria, schizencephaly, hemimegalencephaly, heterotopia, and polymicrogyria. Neuronal heterotopia is a collection of nerve cells in abnormal locations as a result of arrest of their radial migration, improper formation, or destruction of the radial glial fiber. We reported a case of neuronal heterotopia with brief review of related literatures.