SNCA and Parkinson disease: A phase I trial of the FDA-approved histone deacetylation inhibitor, Glycerol Phenylbutyrate, preliminarily reported increased plasma concentrations of a-synuclein in both the PD patients and healthy age-matched controls (ClinicalTrial.gov ID: NCT02046434), suggesting that this mechanism of action may increase the clearance of α-syn from the human brain.