SNCA and Parkinson disease: For over two decades, since the discovery of the first missense mutation in the gene encoding α-synuclein as the cause of a familial form of Parkinson’s disease (PD) (Polymeropoulos et al., 1997) and identification of α-synuclein as a major component of Lewy bodies and Lewy neurites (Spillantini et al., 1997, Spillantini et al., 1998), malfunction of this protein is considered as a key molecular event in the pathogenesis of PD and certain other diseases collectively known as α-synucleinopathies (Galvin et al., 2001, Goedert, 1999, Spillantini and Goedert, 2000).