Kwon et al. demonstrated that individuals with Parkinson’s disease have a higher prevalence of Parkinson’s disease and altered expression of key myokines, including apelin, beta-aminoisobutyric acid (BAIBA), IGF-1, irisin, sestrin, IL-15, and the vascular endothelial growth factor (VEGF), alongside increased pro-catabolic mediators such as IL-6 and myostatin. Here, APLN is linked to Parkinson disease.