SNCA and Parkinson disease: In other preclinical studies, polyethylenimine‐siRNA and RVG‐exosome‐siRNA targeting α‐synuclein transcripts also demonstrated a robust reduction of both overexpressed human SNCA mRNA and α‐synuclein protein in the striatum of a PD mouse model and delayed the development of α‐synuclein pathology.202, 203