Here, we aimed to gain a systematic understanding of how each of these factors relate by examining neuropathology, GCase activity, and glycosphingolipid levels in parallel across four brain regions of idiopathic PD/PDD/DLB, GBA1-PD/PDD/DLB, LRRK2-PD/PDD and matched controls. The gene discussed is GBA1; the disease is Parkinson disease.