The majority of investigations regarding the pathogenic mechanisms underlying cell death in PD have emphasized post-mortem studies, genetically altered animals and neuronal cultures, but a role for non-neuronal cells in the pathoetiology of PD by investigations into glial cell line responses, may lead to a better understanding of the role of α-synuclein in cell-cell communication and the neuron-glia relationship in PD. This evidence concerns the gene SNCA and Parkinson disease.