In the future, detailed analysis of the induction of inflammation, synaptic terminal abnormalities, axonal degeneration or neurodegeneration in the α-synuclein PFFs introduced mice or cells and clarification of the cytotoxicity of α-synuclein aggregates and/or phosphorylated α-synuclein will lead to clarification of the pathogenesis of α-synucleinopathies and development of therapeutic methods. Here, SNCA is linked to synucleinopathy.