@article{1411222cfb7448849e05f40aaf556a70,
title = "Early-onset epileptic encephalopathies: Ohtahara syndrome and early myoclonic encephalopathy",
abstract = "Ohtahara syndrome and early myoclonic encephalopathy are the earliest presenting of the epileptic encephalopathies. They are typically distinguished from each other according to specific clinical and etiologic criteria. Nonetheless, considerable overlap exists between the two syndromes in terms of clinical presentation, prognosis, and electroencephalographic signature. Newer understandings of underlying etiologies of these conditions may support the previously suggested concept that they represent a single spectrum of disease rather than two distinct disorders. We review both syndromes, with particular focus on the underlying genetics and pathophysiology and implications regarding the classification of these conditions.",
author = "Beal, {Jules C.} and Koshi Cherian and Moshe, {Solomon L.}",
note = "Funding Information: Ohtahara syndrome and early myoclonic encephalopathy, as electroclinical syndromes, are defined by their clinical presentations and specific electroencephalographic findings. Based on these criteria, they are traditionally distinguished from each other according to differing seizure types, differences in their pattern of suppression burst, and differing etiologies. Specifically, in its purest form, Ohtahara syndrome is thought to result mostly from structural malformations, whereas early myoclonic encephalopathy is associated with metabolic abnormalities. However, considerable clinical overlap between these conditions can occur. Newer understandings of the genetic and pathophysiologic mechanisms underlying these diseases have revealed further similarities between them. Broadly speaking, both syndromes frequently seem associated with conditions that lead to abnormal neuronal migration, possibly leading to both structural brain abnormalities and a functional disconnection between the cortex and the deep brain and brainstem [20,26,34,46,48] . The prominence of brainstem abnormalities in both syndromes similarly indicates a disconnect between the cortex and subcortical structures. This so-called “cortical deafferentation” may play a role in the intractable nature of the seizures as well the prevalence of tonic seizures in both syndromes [34,36,46] . Thus, to think of Ohtahara syndrome and early myoclonic encephalopathy as part of a spectrum may be possible. The multiple etiologies identified in these conditions lead to similar pathophysiologic pathways. These pathways may result in a range of similar disease states involving tonic seizures, a suppression burst electroencephalographic pattern, onset during infancy, and progressive encephalopathy with psychomotor retardation. The two syndromes may therefore not involve two distinct diseases, but rather may form part of a continuum of disease. S.L.M. has received research support from the National Institutes of Health (grant R01 NS20253 as principal investigator, grant R01-NS43209 as investigator, and grant 2UO1-NS45911 as investigator) and the Heffer Family Foundation . ",
year = "2012",
month = nov,
doi = "10.1016/j.pediatrneurol.2012.06.002",
language = "English (US)",
volume = "47",
pages = "317--323",
journal = "Pediatric Neurology",
issn = "0887-8994",
publisher = "Elsevier Inc.",
number = "5",
}