SNCA and Parkinson disease: Based on evidence that protein aggregation constitutes an inherent phenomenon of aging, imbalances of α-synuclein levels increases with age.As an aggregation-prone and amyloid-forming protein,it is reasonable to assume that the detecting epitope can be conformationally masked in aggregates, which then remain undetected in the assay,which may partly explain the decreased trend of α-synuclein levels with age in PD patients.