SNCA and Parkinson disease: We and others have recently proposed that histopathological confirmation of PD may be advanced by pre-mortem biopsies demonstrating phosphorylated Ser129-alpha-synuclein (p-alpha-syn) deposition within neurons and neurites of the enteric nervous system, the submandibular gland, or the skin, closely resembling the central nervous system pathology [5, 6, 8, 20, 26, 39].