Frontal cortex (9 PD-GBA1, 11 idiopathic PD, 6 controls), putamen (6 PD-GBA1, 9 idiopathic PD, 6 controls), substantia nigra (8 PD-GBA1, 13 idiopathic PD, 3 controls). Here, GBA1 is linked to Parkinson disease.