As shown by the transfection experiments of PTPN11 and MAP2K, while the solitary activation of the mTOR pathway causes FCD type II and HME, the abnormal activation of both the mTOR and RAS/MAPK pathways during brain development may lead to other types of epileptogenic lesions such as LEATs or FCD types I and III. The gene discussed is PTPN11; the disease is isolated focal cortical dysplasia type II.