Accordingly, in hiPSC-derived dopaminergic neurons from sporadic PD patients, as well as from patients carrying mutations in GBA, LRRK2, DJ-1, Parkin and SNCA (A53T, triplication) with decreased lysosomal β-glucocerebrosidase (GCase) activity, treatment with small-molecule enhancers of GCase has resulted in reduced αSyn levels and associated toxicity. The gene discussed is GBA1; the disease is Parkinson disease.