The precise causes of neurodegeneration in this disease have not been definitively established; however, abundant evidence has accumulated demonstrating the presence of neuroinflammation in PD patients, and glial cell activation, proinflammatory signaling molecules, and oxidative stress are now considered to be key mechanisms that contribute to neurodegeneration in PD.46 Another highly relevant factor in the pathogenesis of PD is the protein alpha-synuclein (αSYN). Here, SNCA is linked to Parkinson disease.