In a recent study, the oligomeric form of α-synuclein or o-α-syn was detected for the first time in autonomic nerve terminals in skin biopsy samples using a proximity ligation assay; a significantly higher deposition of o-α-syn was seen in 38 consecutive PD patients in comparison to 29 consecutive healthy controls (Mazzetti et al., 2020). Here, SNCA is linked to Parkinson disease.