International League Against Epilepsy classification and definition of epilepsy syndromes with onset at a variable age: position statement by the ILAE Task Force on Nosology and Definitions

Abstract

The goal of this paper is to provide updated diagnostic criteria for the epilepsy syndromes that have a variable age of onset, based on expert consensus of the International League Against Epilepsy Nosology and Definitions Taskforce (2017–2021). We use language consistent with current accepted epilepsy and seizure classifications and incorporate knowledge from advances in genetics, electroencephalography, and imaging. Our aim in delineating the epilepsy syndromes that present at a variable age is to aid diagnosis and to guide investigations for etiology and treatments for these patients.

Methodology for classification and definition of epilepsy syndromes with list of syndromes: Report of the ILAE Task Force on Nosology and Definitions

“…23 • Epilepsy syndromes with onset at a variable age. 24 In person, Task Force discussions also focused on two additional important questions.…”

“…The latter description and 27 other points added/modified in the revision process were included in the final (third) Delphi survey, which had a response rate of 58/67 (87%), and consensus was reached on all points. The diagnostic criteria and detailed summaries of each syndrome are discussed in the respective position papers 21–24 …”

“…The diagnostic criteria and detailed summaries of each syndrome are discussed in the respective position papers. [21][22][23][24] 4 | DISCUSSION Epilepsy syndromes have been recognized for >50 years, and their identification is critical in guiding investigations, selecting optimal therapy, and assisting with prognostic counseling on seizure outcome and comorbidities. Although both the 1985 and 1989 Classifications of the Epilepsies refer to the existence of syndromes, syndromespecific diagnostic criteria have not been defined and subjected to a formal consensus process.…”

“…Recognition of these syndromes is important, as it guides optimal treatment. MTLE-HS and Rasmussen syndrome are included in the epilepsy syndromes with onset at a variable age, 24 HHE is included in the epilepsy syndromes with onset in childhood, 23 and gelastic seizures with hypothalamic hamartoma are included in the epilepsy syndromes with onset in neonates and infants. 22 Furthermore, there are gene-specific epilepsy syndromes, characterized by distinct electroclinical phenotypes due to a pathogenic variant in a single gene.…”

Classification and definition of epilepsy. Position paper by the International League Against Epilepsy on Nosology and Definitions of Epilepsy Syndromes dated 2021

“…Однако за последние 2 десятилетия были открыты гены, ответственные за развитие некоторых форм эпилепсии. Были описаны электроклинические фенотипы, связанные с мутациями в генах CDKL5 [17], MeCP2 [18,19], PCDH19 [20][21][22], STXBP1 [23] и при инверсии-дупликации 15-й хромосомы [24]. Кроме того, были установлены некоторые характерные электроклинические фенотипы при эпилепсиях с различными структурными, метаболическими, иммунными и инфекционными причинами [3].…”