In agreement, in vivo data from preclinical mouse models of PD, MPTP model (Jackson-Lewis and Przedborski, 2007) and transgenic MitoPark mice (Ekstrand and Galter, 2009), indicated an early PROK2 upregulation in nigral DA neurons before the onset of neuronal degeneration and motor deficits. The gene discussed is PROK2; the disease is Parkinson disease.