GLB1 and Gaucher disease: There is no alteration in lysosomal mass in Gaucher disease or Parkinson’s disease with GBA mutation fibroblasts; the number of acidic vesicles (Lyso-ID), LAMP1 protein levels and beta-galactosidase activity does not differ between Gaucher disease, Parkinson’s disease with GBA mutation, non-manifesting carrier and control (Fig. 4A).