SNCA and Parkinson disease: At pathological levels of iron, as those observed in MSA and PD, an overexpression of α-synuclein could be expected, which has been implicated with the development of α-synuclein pathology supported by observations that multiplications of the α-synuclein encoding gene (SNCA) are associated with genetic forms of PD and dementia with Lewy bodies [144,145,146].