PROJECT SUMMARY Neonatal seizures due to brain injury (acute symptomatic seizures) are associated with high risk of post- neonatal epilepsy. Although clinical risk factors can help predict which children are at highest risk for epilepsy, little is known about how genetic factors modify the risk for epilepsy after acute symptomatic neonatal seizures. The proposed “Neonatal Seizure Registry – GENetics of Epilepsy (NSR-GENE)” study will test the central hypothesis that children who develop post-neonatal epilepsy are more likely to have pathogenic variants in epilepsy genes, and enrichment in single nucleotide polymorphisms within key inflammatory, neurotransmitter transport and homeostasis, and neurotrophic gene pathways as compared with children who do not develop unprovoked seizures before age five years, and that these can be added to traditional clinical risk factors to predict epilepsy after neonatal seizures. This observational study leverages the infrastructure of the nine center Neonatal Seizure Registry, to which we have recruited >300 children with acute symptomatic neonatal seizures (NCT02789176, NCT04337697). This unique cohort of children and their parents will be invited to participate in non-invasive genetic testing. Using neonatal clinical, EEG, and MRI measures available through the Registry, along with genetic testing results, we will build robust models to predict risk of epilepsy and elucidate mechanisms of epileptogenesis. We will test our hypotheses by pursuing the following specific aims: Aim 1: Determine whether there is an increased incidence of pathogenic coding SNVs and gene rich CNVs within epilepsy genes among children with acute provoked neonatal seizures and post-neonatal epilepsy compared to those without subsequent epilepsy; Aim 2: Determine whether an increased incidence of non-coding SNPs with a priori linkage to epilepsy is associated with the risk of post-neonatal epilepsy; Aim 3 Develop prediction rules to stratify neonates based on risk for post-neonatal epilepsy. This innovative proposal will maintain an existing, multicenter cohort enrolled from US centers that employ state-of-the-art technology for diagnosis and investigation of neonatal seizures, and targets research priorities of parents and clinicians. This carefully designed study will provide novel, clinically relevant answers to key questions about epilepsy in this highly vulnerable patient population. Results will inform the subsequent design of intervention studies and programs designed to reduce the risk of epilepsy after early life seizures.