Therefore, we concluded that AEG-1 was an important endogenous factor for protecting nigral DA neurons from aberrant apoptotic signaling pathway in the adult brain and that the maintenance of increased levels of AEG-1 in nigral DA neurons in patients with PD, in combination with therapeutic agents, such as an Akt/mTORC1 signaling activator, may be a highly promising therapeutic strategy to maximize the functional recovery of the damaged nigrostriatal DA system (Fig. 6). The gene discussed is AKT1; the disease is Parkinson disease.