PD, dementia with Lewy bodies, and multiple system atrophy are characterized by abnormal accumulation of α-synuclein, an abundant neuronal protein, and thus referred to as synucleinopathies.8 The amyloid fibril form of α-synuclein is a crucial component of Lewy bodies, the major pathological intracytoplasmic inclusion typically observed in synucleinopathies. Here, SNCA is linked to Parkinson disease.