Epileptic encephalopathies are an epileptic condition characterized by epileptiform abnormalities associated with progressive cerebral dysfunction. In the classification of the International League Against Epilepsy eight age-related epileptic encephalopathy syndromes are recognized. These syndromes include early myoclonic encephalopathy and Ohtahara syndrome in the neonatal period, West syndrome and Dravet syndrome in infancy, myoclonic status in nonprogressive encephalopathies, and Lennox-Gastaut syndrome, Landau-Kleffner syndrome, and epilepsy with continuous spike waves during slow wave sleep in childhood and adolescences. Other epileptic syndromes such as migrating partial seizures in infancy and severe epilepsy with multiple independent spike foci may be reasonably added. In this paper, we provide an overview of epileptic encephalopathies including clinical neurophysiological features, cognitive deterioration, and management options especially that these conditions are generally refractory to standard antiepileptic drugs.

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Objective. Epileptic encephalopathy (EE) is difficult to diagnose and manage. It can be caused by a variety of disorders, and its aetiology may guide management and prognosis. The human gene for WW domain-containing oxidoreductase (WWOX) has been associated with epileptic encephalopathy, which presents in infancy with seizures, psychomotor delay, microcephaly, and optic atrophy. Methods. We report nine patients with WWOX-related EE from six families. We provide detailed descriptions of clinical presentations, imaging findings, neurophysiological manifestations, and related mutations. Whole-exome sequencing (WES) was used to identify the mutations in the WWOX gene. Results. We established correlations between genotype and phenotype in our cases and previously reported cases. Significance. Our data support previously reported findings regarding WWOXrelated EE, indicating the importance of the human WWOX gene in brain development and the association between WWOX mutations and EE. Our study also highlights the power of WES, particularly in clinically challenging cases.

Tuberous sclerosis complex (TSC) is a neurocutaneous syndrome with an autosomal dominant pattern of inheritance. It is a multisystem genetic disease caused by mutations in the TSC1 and TSC2 genes. The neuroradiographic findings of TSC include cortical dysplasia (cortical tubers and cerebral white matter radial migration lines), subependymal nodules, and subependymal giant cell astrocytoma. In this article, we describe an interesting case of TSC with an extremely rare radiographic finding of focal right megalencephaly. Molecular genetic testing detected a heterozygous c.3814+2T>G (p.?) variant, not previously described in the literature. As per the 2012 International Tuberous Sclerosis Complex Consensus Group guidelines and the findings of the genetic testing, this mutation most probably should be considered as a pathogenic variant. There are few cases of hemimegalencephaly (HME) reported in the literature, associated with TSC. To our knowledge focal megalencephaly is an extremely rare neuroradiographic finding in patients with TSC and has been previously reported only once by Griffiths et al based on clinical diagnostic criteria. Despite the uncommon association, TSC is the only neurocutaneous syndrome with similar histological appearance to HME. It is recognized that the pathological features in TSC and HME are due to abnormal cell proliferation, migration, and organization which could also be a possible mechanism for the development of focal megalencephaly. The uncommon association of HME and TSC with cytological similarities makes us wonder if there could be similarities in the pathogenesis of these two conditions. The advances in molecular genetic testing, increasing use of next-generation sequencing, and discovery of new pathogenic variants could answer some of these questions.