SNCA and Parkinson disease: Furthermore, glucosylceramide, which is elevated in Niemann–Pick type C1, has been demonstrated to be elevated in PD (Mielke et al. 2013), where it has been demonstrated to induce α-synuclein aggregation (Zunke et al. 2018) and enhance neuronal susceptibility to α-synuclein toxicity (Henderson et al. 2020).