TS-002279 — What: gene therapy for pediatric epileptic encephalopathy resultant from mutations in SLC6A1 gene Six new gene replacement products New shRNAs for gene knockdown New delivery route and dosing ranges Why: pediatric epileptic encephalopathy Current treatment is limited to symptomatic treatment, primarily by use of antiepileptic drugs How: single stranded AAV serotype 9 that will provide a wildtype copy of SLC6A1 to address haploinsufficiency resultant from mutations in one copy of the SLC6A1 gene Delivered through cerebrospinal fluid (CSF) via injection