Once in the brain, oligomeric α-synuclein contributes to PD pathogenesis through its canonical mechanism: toxic protofibrils cause disruption of cellular homeostasis and induction of neuronal death through inhibition of synaptic signaling, alteration of cytoskeletal dynamics, loss of protein degradative ability, and mitochondrial fragmentation [45]. The gene discussed is SNCA; the disease is Parkinson disease.