The enhanced aggregation of α-synuclein and impairment in the autophagosome biogenesis and autophagosome-lysosome fusion were observed in the dopaminergic neurons derived from the iPSC of PD patients carrying GBA1 mutations, suggesting an increased level of α-synuclein may cause the autophagic/lysosomal system dysfunction. The gene discussed is GBA1; the disease is Parkinson disease.