SNCA and Alzheimer disease: The deposition of β-sheet containing amyloid aggregates featured many neurodegenerative diseases, such as amyloid-β (Aβ) and tau in Alzheimer’s disease (AD), α-synuclein in Parkinson’s disease (PD), and TAR DNA-binding protein (TDP) 43 in amyotrophic lateral sclerosis (ALS), which causes inflammation, neuronal dysfunction, movement and cognition defects.