CSF neurogranin is also decreased in patients with PD (n = 157), PD with dementia (n = 29), DLB (n = 11), MSA (n = 26), and PSP (n = 21) compared with controls (n = 47) and patients with AD (n = 124), emphasizing the importance of synaptic dysfunction in these parkinsonian disorders [83]. This evidence concerns the gene NRGN and Alzheimer disease.