MAPT and Parkinson disease: PBA is a U.S. Food and Drug Administration approved drug (outside of neurological indications) that functions as a chemical chaperone by binding to exposed hydrophobic regions of proteins to prevent aggregation [142], whereas Anle138b has been shown to bind neurotoxic oligomers of PrP, α-Syn, and tau [143,144] and is currently in clinical trials for Parkinson's disease [145].