MANF and Parkinson disease: The closely related trophic factors mesencephalic astrocyte-derived neurotrophic factor (MANF) (Petrova et al., 2003) and cerebral/conserved dopamine neurotrophic factor (CDNF) (Lindholm et al., 2007) similarly provide neuroprotection in various animal models of PD (Airavaara et al., 2012).