The mechanistic target of rapamycin (mTOR) signalling pathway serves as a ubiquitous regulator of cell metabolism, growth, proliferation and survival. The main cellular activity of the mTOR cascade funnels through mTOR complex 1, which is inhibited by rapamycin, a macrolide compound produced by the bacterium Streptomyces hygroscopicus. Pathogenic variants in genes encoding upstream regulators of mTOR complex 1 cause epilepsies and neurodevelopmental disorders. Tuberous sclerosis complex is a multisystem disorder caused by mutations in mTOR regulators TSC1 or TSC2, with prominent neurological manifestations including epilepsy, focal cortical dysplasia and neuropsychiatric disorders. Focal cortical dysplasia type II results from somatic brain mutations in mTOR pathway activators MTOR, AKT3, PIK3CA and RHEB and is a major cause of drug-resistant epilepsy. DEPDC5, NPRL2 and NPRL3 code for subunits of the GTPase-activating protein (GAP) activity towards Rags 1 complex (GATOR1), the principal amino acid-sensing regulator of mTOR complex 1. Germline pathogenic variants in GATOR1 genes cause non-lesional focal epilepsies and epilepsies associated with malformations of cortical development. Collectively the mTORopathies are characterised by excessive mTOR pathway activation and drug-resistant epilepsy. In the first large-scale precision medicine trial in a genetically-mediated epilepsy, everolimus (a synthetic analogue of rapamycin) was effective at reducing seizure frequency in people with tuberous sclerosis complex. Rapamycin reduced seizures in rodent models of DEPDC5-related epilepsy and focal cortical dysplasia type II. This review outlines a personalised medicine approach to the management of epilepsies in the mTORopathies. We advocate for early diagnostic sequencing of mTOR pathway genes in drug-resistant epilepsy, as identification of a pathogenic variant may point to an occult dysplasia in apparently non-lesional epilepsy or may uncover important prognostic information including, an increased risk of sudden unexpected death in epilepsy in the GATORopathies or favourable epilepsy surgery outcomes in focal cortical dysplasia type II due to somatic brain mutations. Lastly, we discuss the potential therapeutic application of mTOR inhibitors for drug-resistant seizures in GATOR1-related epilepsies and focal cortical dysplasia type II.

Objective: Recent clinical trials have shown that cenobamate substantially improves seizure control in focal-onset drug-resistant epilepsy (DRE). However, little is known about cenobamate's performance in highly active (≥20 seizures/ month) and ultra-refractory focal epilepsy (≥6 failed epilepsy treatments, including antiseizure medications [ASMs], epilepsy surgery, and vagus nerve stimula-How to cite this article: