The appendix of PD patients had increased α-syn protein levels (SNCA), along with decreases of GPNMB, NAMPT, vacuolar protein sorting 35 ortholog (VPS35) and heat shock 70 kDa protein 8 (HSPA8/HSC70), which are all linked to PD risk and affect neuronal survival23,57,59–62. This evidence concerns the gene HSPA8 and Parkinson disease.