SNCA and Parkinson disease: For example, α-Synuclein, a presynaptic neuronal protein linked genetically and neuropathologically to Parkinson’s disease, once SUMOylated, is incorporated into sEVs, released into the extracellular milieu and readily internalised by other cells in the central nervous system, transferring toxic alpha synuclein oligomers in a cell-to-cell manner [104].