CP and Parkinson disease: However, major advances in knowledge about iron metabolism during this period would later have significant implications for Parkinson disease research, including studies of the iron storage protein ferritin (Dognin and Crichton 1975) and ferroxidase proteins such as ceruloplasmin (Curzon and O'Reilly 1960), although ceruloplasmin was not linked with parkinsonism until several decades later (Ayton et al. 2013).