The importance of the α-synuclein protein (non-amyloid component precursor; NACP) was confirmed through its recognition as a major component of both Lewy bodies, the pathological hallmark of PD and dementia with Lewy bodies (DLB), and of glial cytoplasmic inclusions in multiple system atrophy (MSA) [4]. The gene discussed is SNCA; the disease is Parkinson disease.