Characterization of 13 Novel Genetic Variants in Genes Associated with Epilepsy: Implications for Targeted Therapeutic Strategies.

BACKGROUND: Childhood epilepsies are caused by heterogeneous underlying disorders where approximately 40% of the origins of epilepsy can be attributed to genetic factors. The application of next-generation sequencing (NGS) has revolutionized molecular diagnostics and has enabled the identification of disease-causing genes and variants in childhood epilepsies. The objective of this study was to use NGS to identify variants in patients with childhood epilepsy, to expand the variant spectrum and discover potential therapeutic targets. METHODS: In our study, 55 children with epilepsy of unknown etiology were analyzed by combining clinical-exome and whole-exome sequencing. Novel variants were characterized using various in silico algorithms for pathogenicity and structure prediction. RESULTS: The molecular genetic cause of epilepsy was identified in 28 patients and the overall diagnostic success rate was 50.9%. We identified variants in 22 different genes associated with epilepsy that correlate well with the described phenotype. SCN1A gene variants were found in five unrelated patients, while ALDH7A1 and KCNQ2 gene variants were found twice. In the other 19 genes, variants were found only in a single patient. This includes genes such as ASH1L, CSNK2B, RHOBTB2, and SLC13A5, which have only recently been associated with epilepsy. Almost half of diagnosed patients (46.4%) carried novel variants. Interestingly, we identified variants in ALDH7A1, KCNQ2, PNPO, SCN1A, and SCN2A resulting in gene-directed therapy decisions for 11 children from our study, including four children who all carried novel SCN1A genetic variants. CONCLUSIONS: Described novel variants will contribute to a better understanding of the European genetic landscape, while insights into the genotype-phenotype correlation will contribute to a better understanding of childhood epilepsies worldwide. Given the expansion of molecular-based approaches, each newly identified genetic variant could become a potential therapeutic target.

Provoked seizures at the onset of progressive disease contribute to diagnosis delay - A tertiary center experience in a cohort of 22 children with CLN2.

PURPOSE: The evaluation of epilepsy features and factors with impact to diagnosis delay in children with CLN2. METHOD: The study included children with CLN2 treated from 2000 to 2020. Diagnosis was confirmed by: TPP1 deficiency and/or TPP1 gene mutation or pathognomonic electron microscopy findings. The seizure features were evaluated: the age of onset, provocation, semiology and EEG. The disease severity was assessed by CLN2 Clinical Rating Scale (CLN2-CRS). Statistical analysis included T test, chi-square test, Wilcoxon-Mann-Whitney test, using SPSS statistics 25. RESULT: The study included 22 children with CLN2. Seizures were experienced by all cases at the early stage of disease, preceded by language delay in 18, and behavior problems in 14 pts. The first seizure was provoked in 9 children at mean age of 33.8 ± 4.6 months, and unprovoked in 13 at mean age of 34.6 ± 2.7 months. In patients with provoked first seizure, the average period from the first seizure to diagnosis was longer (35.1 months), with lower CLN2-CRS, then in those with unprovoked (23.8 months) first seizures (p < 0.008). Initial seizures were generalized tonic-clonic (Pampiglione and Harden, 1973 Feb) [8], atonic (Pampiglione and Harden, 1973 Feb) [8], and focal (Beltrán et al., 2018 Aug) [4], with recurrence within two months. With progression, the patients experienced multiple seizure types, and 1/3 suffered status epilepticus. CONCLUSIONS: Provoked seizures at the onset of CLN2 have impact to diagnosis delay. The red flags are: preceding language delay and behavior problems, later FS onset comparing to the typical age, atonic, focal and long-lasting seizure, and recurrence of seizures within two months.

The improvement in diagnosis and epilepsy managing in children with progressive myoclonus epilepsy during the last decade - A tertiary center experience in cohort of 51 patients.

The aim of the study was to explore whether diagnosis and managing children with progressive myoclonus epilepsy (PME) were improved during the last decade. METHODS: The retrospective study included children with PME treated in the Institute during the last 25 years. Investigation time was divided in two periods (groups): before December 2010 (the first group) and after this period up to December 2019 (the second group). Inclusion criteria are as follows: patients aged from 0.2-18 years and with PME. Evaluated parameters are etiology, age at seizure onset, diagnosis delay, epilepsy phenotype, and, as a measure of epilepsy control - status epilepticus (SE) frequency and recurrence rate. Statistical analysis included the following tests: Chi-Square, Mann-Whitney, and analysis of variance (ANOVA), using SPSS version 25. RESULTS: The study included 51 patients, 27 in the first, and 24 in the second group. The underlying diseases were: neuronal ceroid lipofuscinosis (NCL; 30), Gaucher (5), Niemann-Pick (4), mitochondrial (4), Lafora (3), Krabbe (2), and KCNC1 gene mutation (2). The average duration from initial symptoms to diagnosis was 3.2 ±â€¯3 years (first group) vs. 1.4 ±â€¯0.9 years (second). Both SE frequency rate (55.5% vs. 37.5%) and recurrence rate (66.7% vs. 22.2%) were higher in the first group, showing tendency towards, but not statistically significant difference. CONCLUSION: The diagnosis and epilepsy managing children with PME were improved during the last decade. Earlier genetic diagnosis, appropriate antiseizure medications, education of parents/caregivers of children in high risk for SE, and availability of effective prehospital rescue medications contributed to significantly decreased frequency and recurrence rate of SE.

The features of neonatal seizures as predictors of drug-resistant epilepsy in children.

PURPOSE: The aim of this study was to evaluate the predictive value of the features of neonatal seizures for pharmacoresistant epilepsy in children. METHOD: This is a retrospective study that involved all children diagnosed as having epilepsy who had neonatal seizures and who were hospitalized at the Neurology Department of the Mother and Child Healthcare Institute in Belgrade from January the 1st 2017 until December 31st 2017. The following parameters and their impact on the outcome were investigated: perinatal data, the characteristics of epileptic seizures in the neonatal period, and the response to anticonvulsant treatment. The presence of pharmacoresistance was observed as an outcome parameter. Univariate and multivariate logistic regression analyses were used to define predictors of drug-resistant epilepsy. RESULTS: The study involved 55 children, 35 (63.6%) male and 20 (36.4%) female. The average age of the children at the end of the observation period was 5.17 years (min: 0.25, max: 17.75, iqr (interquartile range): 6.92). Pharmacoresistant epilepsy was found in 36 (65.5%) children. The most common type of epilepsy was focal, which affected 30 patients (54.5%), than generalized, which affected 15 patients (27.3%), and combined generalized and focal, which affected 8 patients (14.5%). At the end of the observation period, 28 patients (50.9%) had no seizures, while 14 (25.5%) had daily seizures. It was found that the pharmacoresistant neonatal seizures and metabolic-genetic disorders were predictive factors of the occurrence of pharmacoresistant epilepsy. CONCLUSION: Patients prone to developing pharmacoresistant epilepsy might be identified as early as the neonatal and early infant period. High incidence of asphyxia cooccurring with established genetic-metabolic disease further emphasizes need for genetic testing in infants with neonatal seizures including in the presence of hypoxic-ischemic injury.