HSPA9 and Parkinson disease: GRP75 has often been linked to PD pathogenesis as reported in studies showing binding properties to PD-associated proteins in the mitochondria (Li et al. 2005; Jin et al. 2005, 2006, 2007; Rakovic et al. 2011) and reduced levels of the protein in postmortem PD brain samples (Jin et al. 2005; Shi et al. 2008; Burbulla et al. 2010).