FNDC5 and Parkinson disease: Several studies have reported beneficial actions of irisin in other neurodegenerative diseases, viz., Parkinson’s disease (PD), multiple sclerosis (MS), cerebral ischemia, ischemic stroke, etc. Irisin has been shown to reduce α-synuclein pathology and protect neurons against α-synuclein preformed fibril (PFF)-induced neurotoxicity at least in part by increasing the lysosomal degradation of pathologic α-synuclein [78].