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Objectives: Two configurations of TTTTA/TTTCA expansion in SAMD12 have been identified in familial cortical myoclonic tremor with epilepsy type 1 (FCMTE1). This study investigated the clinical and neurophysiological features of FCMTE1 and their association with TTTTA/TTTCA expansion patterns., Methods: In total, 76 patients from 20 Chinese pedigrees were enrolled. Genetic (TTTTA/TTTCA configuration), clinical (e.g., onset, medication, prognosis, and anticipation) and neurophysiological examination (e.g., electroencephalogram and magnetoencephalography) data were evaluated, and associations between these parameters were analyzed., Results: All patients carried the TTTTA/TTTCA expansion mutation, 19 displayed the (TTTTA)exp(TTTCA)exp (type I) configuration and 1 displayed the (TTTTA)exp (TTTCA)exp(TTTTA)exp (type II) configuration. All patients manifested as progressive tremor, but symptoms of patients carrying type II expansion were more severe. The onset of tremor but not generalized tonic and clonic seizures displayed clinical anticipation between generations of 7 pedigrees, but the pedigree carrying the type II mutation did not show anticipation. Nanopore sequencing showed that the repeats expanded during maternal/offspring transmission (pedigree #7) but shrank during paternal/offspring transmission (pedigree #9). Magnetoencephalographic dipoles were localized in the right frontal lobe near the central sulcus in 4 patients carrying the type I mutation and on the left side in one patient carrying the type II mutation., Significance: We confirmed the causative roles played by TTTTA/TTTCA repeat expansion in the SAMD12 gene in FCTME1. Both the length and the configuration of the repeats contribute to the clinical and neurophysiological characteristics of the disease., (Copyright © 2021. Published by Elsevier Ltd.)

Purpose: This study investigated the duration of generalized tonic-clonic seizure (GTCS) and the factors that prolong GTCS duration., Method: We retrospectively analyzed clinical data collected from a consecutive group of patients who underwent video-electroencephalography (EEG) and experienced at least one GTCS during monitoring. Each seizure was divided into seven phases. The duration of GTCS was defined as the comprehensive duration of each GTCS phase, particularly those of Phase 3 to Phase 7., Results: The mean GTCS duration per patient was 74.6s. The results indicated that patients with an age of seizure onset <2 years exhibited a significantly longer duration than those with an age of seizure onset >2 years (p=0.033). A significant difference was also observed in the duration of GTCS between wakefulness and sleep (wakefulness 76.2 ± 38.5, sleep 66.3 ± 27.8, p=0.017). Our data suggest no significant differences between primary and secondary GTCS. The correlations between the duration of GTCS and many risk factors were also analyzed, including gender, age, neurological examination, cognitive status, family history of epilepsy, location of MRI brain abnormalities, reported seizure frequency at time of admission, number of current AEDs, history of SE, and duration of epilepsy., Conclusions: The mean duration of GTCS was<2 min. The age of seizure onset and the circadian pattern of seizure are the major factors influencing the duration of GTCS., (Copyright © 2015 British Epilepsy Association. Published by Elsevier Ltd. All rights reserved.)