Precision Medicine in Epilepsy: Diagnostic Yield by Next-Generation Sequencing and Genotype-Phenotype Findings in a...

Epilepsy ranks among the most prevalent neurological disorders globally, with a substantial proportion of cases, particularly in pediatric populations, attributed to genetic etiologies. This study provides the first molecular characterization of suspected genetic epilepsy in a pediatric cohort from the Moldova region of Romania. Following the exclusion of 124 patients with secondary acquired or structural causes from an initial cohort of 159, we enrolled 35 individuals with a high suspicion of primary genetic epilepsy, who underwent targeted gene panel testing or whole-exome sequencing (WES). Pathogenic (P) or likely pathogenic (LP) variants were identified in 13 patients (37.1%); variants of uncertain significance (VUSs) were identified in another 13 patients (37.1%), comprising 15 distinct VUSs; and negative results were observed in the remaining 9 patients (25.7%). Genes regulating ion channels and synaptic signaling, notably SCN1A, KCNB1, and GNAO1, were predominantly implicated in early-onset, drug-resistant epileptic encephalopathies, whereas structural copy number variations (CNVs) underpinned syndromic phenotypes. We identified one novel pathogenic variant in SCN1A, thereby expanding the known mutational spectrum. Furthermore, in silico predictions and de novo occurrence patterns supported the pathogenicity of several VUSs, underscoring the critical value of familial segregation analyses. Despite the notable diagnostic yield, the high VUS rate underscores the ongoing need for refined variant interpretation criteria and the integration of functional validation data to improve classification accuracy. Collectively, our findings support the clinical utility of next-generation sequencing (NGS) in informing therapeutic decisions, enabling genetic counseling, and improving prognostic accuracy. These results suggest that NGS should be considered early in the diagnostic workup of unexplained or drug-resistant epilepsy, particularly in patients with clinical features suggestive of a genetic etiology.