SNCA and Parkinson disease: PD is characterized by protein deposition in intraneuronal inclusions, the so-called Lewy bodies (LB) and Lewy neurites (LN) [2,3], whose major component is α-synuclein (α-syn) [4], a 140 amino acid presynaptic protein encoded by the SNCA gene and normally found in both soluble and membrane-associated fractions of the brain [5,6].