Abstracts

Rationale: Early onset epileptic encephalopathy is characterized by repeated seizures beginning within 3 months of birth and severe interictal epileptiform discharge such as burst suppression. Targeted gene panel sequencing has been used as a useful tool for the genetic diagnosis of this disease and is known to enable correlation of genotype-phenotype. Methods: We performed targeted gene panel sequencing of 150 early onset epileptic encephalopathies whose seizure onset was from birth to 3 monthsand identified pathogenic genes. We also investigated the clinical features, treatment, and prognosis of these patients. Results: Of the 150 patients with early onset epileptic encephalopathy, 70 had neonatal epilepsy whose seizure was developed 1 month before birth and other 80 patients started seizures from 1 to 3 months after birth. Of the 150 patients, 58 (38.7%) were able to identify 23 different pathogenic genes. In patients with seizure onset during the neonatal period, pathologic genes were identified in 37 patients (52.9%), indicating a significant higher diagnostic yield than patients group of whose onset of seizure was from 1 to 3 months after birth (p<0.001). Among them, gene mutations of SCN2A, SRXBP1, KCNQ2 and CDKL5 were detected at a high frequency. The 124 patients of total patients (82.7%) were progressed to intractable epilepsy such as West syndrome or Lennox-Gastaut syndrome (LGS). Sodium channel blockers, vigabatrin, prednisolone and ketogenic diet were effective in treating these patients based on pathogenic variants. Conclusions: Targeted gene panel sequencing shows a high yield of pathogenic variants in the diagnosis of early onset epileptic encephalopathy, especially in patients with neonatal onset of seizure. The early diagnosis of early onset epileptic encephalopathy may improve the prognosis of patients by early selection of treatment modalities based on pathogenic variants of patients. Funding: None