SNCA and Parkinson disease: Also as mentioned above abnormal aggregation and/or mutation of proteins such as beta amyloid, DJ-1, PTEN-induced putative kinase 1, parkin, leucine-rich repeat kinase 2 and α-synuclein have been observed in PD (el-Agnaf and Irvine, 2002; Nunomura et al., 2007; Alcalay et al., 2009).