Similar α-Synuclein staining in the colon mucosa in patients with Parkinson's disease and controls

ABSTRACT Background The gut is proposed as a starting point of idiopathic IPD, but the presence of α‐synuclein in the IPD colon mucosa is debated. Objectives The objective of this study was to evaluate if α‐synuclein in the colon mucosa can serve as a biomarker of IPD. Methods Immunohistochemistry was used to locate and quantify in a blinded approach α‐synuclein in the mucosa from biopsies of the right and left colon in 19 IPD patients and 8 controls. Results Total α‐synuclein was present in all but 1 IPD patients and in all controls; phosphorylated α‐synuclein was present in all subjects. There was no intensity difference depending on disease status. Staining of total α‐synuclein was stronger in the right colon (p = .04). Conclusions Conventional immunohistochemistry α‐synuclein staining in colon mucosal biopsies cannot serve as a biomarker of idiopathic PD. These findings do not contradict the assumption of disease starting in the colon, and a colon segment‐specific risk for disease initiation can still be hypothesized. © 2016 International Parkinson and Movement Disorder Society