GBA1 and Parkinson disease: These αS levels secreted by pMac were comparable to those secreted by iPSC-dopaminergic neuronal cultures (previously published14, measured using the same assay platform), which ranged from ~100–400 pg/ml in 2-day supernatant from controls and ~200–800 pg/ml for lines from patients harbouring N370S mutations in the Parkinson’s disease-associated gene for glucocerebrosidase, GBA.