EGLN1 and Parkinson disease: The abnormal up-regulation of the EGLN1 gene in PD brains, recently described as a proline hydroxylase-2 (PHD2) belonging to the iron- and 2-oxoglutarate-dependent dioxygenase superfamily (Epstein et al. 2001), may exacerbate the OS status and promote iron-induced aggregation of α-synuclein.