For example, mTOR-pathway-activating somatic mutations cause two types of intractable epilepsy (hemimegalencephaly and focal cortical dysplasia) depending on the time of occurrence of the mutation and VAFs (10%–30% VAFs in hemimegalencephaly, and 1%–10% of VAFs in focal cortical dysplasia) [8–10]. The gene discussed is MTOR; the disease is hemimegalencephaly.