ProSAAS has been shown to block the fibrillation and aggregation of both Abeta 1–42 and alpha synuclein [reviewed in [12]]; to relieve endoplasmic reticulum stress [13,14]; and to prevent the death of nigral neurons when virally expressed in a synuclein overexpression model of Parkinson’s disease [15], supporting a cytoprotective function. Here, SNCA is linked to Parkinson disease.