SNCA and Parkinson disease: The histopathology of PD is characterized by SNCA deposits in neuronal cell bodies (Lewy bodies) and neuronal processes (Lewy neurites), leading to a degeneration of the nigrostriatal DA system (Box 1), with neuronal loss and reactive gliosis in the substantia nigra (Box 1) (Dickson, 2012) and extranigral regions such as the amygdala, cerebral cortex, spinal cord, and brainstem areas that regulate autonomic functions (Braak et al., 1995; Braak et al., 2007; Del Tredici and Braak, 2012).