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. 2024 Aug 23;97(1):34-50.
doi: 10.1002/ana.27063. Online ahead of print.

Electro-Clinical Features and Functional Connectivity Analysis in SYN1-Related Epilepsy

Vincent Moya Quiros  1 , Ahmed Adham  2   3 , Philippe Convers  1   4 , Gaetan Lesca  5   6 , François Mauguiere  4   7 , Hugo Soulier  1 , Alexis Arzimanoglou  8   9 , Allan Bayat  10   11   12   13 , Hilde Braakman  14 , Jean-Philippe Camdessanche  1 , Philippe Casenave  15 , Laurence Chaton  16 , Yves Chaix  17   18 , Maxime Chochoi  16 , Christel Depienne  19 , Vincent Desportes  20 , Jessie De Ridder  21 , Vera Dinkelacker  22 , Elena Gardella  10   11 , Gerhard J Kluger  23 , Julien Jung  7   24 , Martine Lemesle Martin  25 , Maria Margherita Mancardi  26 , Markus Mueller  27 , Anne-Lise Poulat  20 , Konrad Platzer  28 , Agathe Roubertie  29 , Marijn F Stokman  30 , Anneke T Vulto-van Silfhout  30 , Gert Wiegand  31   32 , Laure Mazzola  1   4
Affiliations

Electro-Clinical Features and Functional Connectivity Analysis in SYN1-Related Epilepsy

Vincent Moya Quiros et al. Ann Neurol. .

Abstract

Objective: There is currently scarce data on the electroclinical characteristics of epilepsy associated with synapsin 1 (SYN1) pathogenic variations. We examined clinical and electro-encephalographic (EEG) features in patients with epilepsy and SYN1 variants, with the aim of identifying a distinctive electroclinical pattern.

Methods: In this retrospective multicenter study, we collected and reviewed demographic, genetic, and epilepsy data of 19 male patients with SYN1 variants. Specifically, we analyzed interictal EEG data for all patients, and electro-clinical data from 10 epileptic seizures in 5 patients, using prolonged video-EEG monitoring recordings. Inter-ictal EEG functional connectivity parameters and frequency spectrum of the 10 patients over 12 years of age, were computed and compared with those of 56 age- and sex-matched controls.

Results: The main electroclinical features of epilepsy in patients with SYN1 were (1) EEG background and organization mainly normal; (2) interictal abnormalities are often rare or not visible on EEG; (3) more than 60% of patients had reflex seizures (cutaneous contact with water and defecation being the main triggers) isolated or associated with spontaneous seizures; (4) electro-clinical semiology of seizures was mainly temporal or temporo-insulo/perisylvian with a notable autonomic component; and (5) ictal EEG showed a characteristic rhythmic theta/delta activity predominating in temporo-perisylvian regions at the beginning of most seizures. Comparing patients with SYN1 to healthy subjects, we observed a shift to lower frequency bands in power spectrum of interictal EEG and an increased connectivity in both temporal regions.

Interpretation: A distinct epilepsy syndrome emerges in patients with SYN1, with a rather characteristic clinical and EEG pattern suggesting predominant temporo-insular involvement. ANN NEUROL 2024.

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Conflict of interest statement

Nothing to report.

Figures

FIGURE 1
FIGURE 1
Graphical representation of intellectual disability, drug‐resistance, truncating/non‐truncating variant state and age at seizure onset in patients with SYN1‐related epilepsy. [Color figure can be viewed at www.annalsofneurology.org]
FIGURE 2
FIGURE 2
EEG samples centered on the onset of the seizure 1 in patient I‐1, with a rhythmic theta‐delta activity on the right temporal region. Filters used: high‐frequency filter 30 Hz and low‐frequency filter 0.53 Hz. EEG = encephalographic; Hz = hertz. [Color figure can be viewed at www.annalsofneurology.org]
FIGURE 3
FIGURE 3
Electroencephalographic interictal occipital (O1–O2) power spectrum frequency analysis, ±2 standard deviations. [Color figure can be viewed at www.annalsofneurology.org]
FIGURE 4
FIGURE 4
Phase locking value functional connectivity metric at 10 Hz (links weaker than 1 standard deviation are not shown). Hz = hertz. [Color figure can be viewed at www.annalsofneurology.org]
FIGURE 5
FIGURE 5
Weighted clustering coefficient (from 0 to 1) and average path length (from 0 to 1). [Color figure can be viewed at www.annalsofneurology.org]
See this image and copyright information in PMC

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