XBP1 and Parkinson disease: Among canonical ER stress response mediators XBP1, GRP94 (HSP90B1), GRP78 (HSPA5), CHOP (DDIT3), PERK (EIF2AK3), ATF6, and IRE1 (ERN1), Genome-wide association (GWA) studies identified a PERK variant (rs7571971) associated with progressive supranuclear palsy [63], and an ATF6 variant (rs10918270) associated with Parkinson’s Disease [64].