SNCA and Alzheimer disease: Most neurodegenerative diseases present intracellular protein aggregation or their extracellular deposition (plaques), such as α-synuclein (α-Syn) in Parkinson’s disease (PD), amyloid beta (Aβ)/tau aggregates in Alzheimer’s disease (AD), superoxide dismutase (SOD) in amyotrophic lateral sclerosis (ALS), or huntingtin protein with glutamine repeats in Huntington’s disease (HD) [1,2].