Here we show that unlike these other compounds, GM1 is neuroprotective in mouse and nonhuman primate MPTP models17,18,21,23, is neuroprotective in an AAV-α-synuclein model that reproduces DA neuron degeneration and dysfunction based on a core molecular feature of PD (i.e., toxicity associated with accumulation of aberrant α-synuclein29), and that these preclinical successes have translated to positive effects in initial clinical trials24,33. Here, SNCA is linked to Parkinson disease.