SNCA and Parkinson disease: The protein alpha-synuclein (α-SYN) is closely linked to the pathogenesis of PD: genetic mutations or multiplication of the gene coding α-SYN, SNCA, cause familial forms of PD, while α-SYN is the main component of the protein aggregates, Lewy bodies and Lewy neurites found in sporadic PD [1-4].