PD-associated Park genes encoding proteins, alpha synuclein, leucine-rich repeat kinase 2 (LRRK2), PTEN-induced putative kinase 1 (PINK1), Parkin, and DJ-1, are associated with iron accumulation in the SN as measured by TCS, demonstrating that iron elevation is an invariable feature of multiple PD modalities (Table 2). This evidence concerns the gene PINK1 and Parkinson disease.