Approximately 90% of α-synuclein deposited in Lewy bodies is phosphorylated at Ser129, whereas ≤4% of total α-synuclein is phosphorylated at this residue in the normal brain [5,6], suggesting that Ser129-phosphorylated α-synuclein is one of the key players leading to the formation of Lewy bodies and may contribute to dopaminergic neurodegeneration in PD. This evidence concerns the gene SNCA and Parkinson disease.