SNCA and Parkinson disease: Although the etiology of PD is yet to be elicited, the spatio-temporal association between Lewy pathology and neurodegeneration, together with evidence from in vitro and in vivo models, suggests that pathologically aggregated forms of alpha-synuclein may contribute to axonal and neuronal damage, formation of Lewy pathology and consequent neuronal loss and disease progression (18–22).