TSC1 and hemimegalencephaly: Somatic variants in genes of mTOR signaling pathway, including TSC1, TSC2, PIK3CA, MTOR, and AKT3, are found in 63% of FCD type II and hemimegalencephaly tissue samples obtained in resective epilepsy surgery;22 some patients with FCD also carry germline pathogenic variants in genes of GATOR1 complex, another regulator of mTOR signaling pathway.23