Additionally, we comprehensively cataloged alpha-synuclein proteoforms in the post-surgical appendix and substantia nigra (SN) of patients with synucleinopathy and neurologically intact controls using top-down mass spectrometry (TD-MS), the gold-standard approach for identifying intact and truncated alpha-synuclein proteoforms (25, 26). The gene discussed is SNCA; the disease is synucleinopathy.