PD patients showed significantly lower α-syn level than the controls (). The level of α-syn decreased significantly with age () and correlated to inversely assigned Hoehn and Yahr stage ().
The level of α-syn in DLB patients was significantly lower than those in patients with AD () and other dementias (). In DLB patients, reduced α-syn level correlated with the lower level of CSF Aβ42 (). Patients with SNCA duplication showed a decrease of CSF α-syn.
The level of total α-syn was lower in PD patients than in age-matched controls. The level of α-syn oligomers was significantly higher in PD patients than in age-matched controls.
Upper and lower rows indicate training and validation cohorts, respectively. The level of α-syn was significantly lower in DLB, PD, and MSA patients than in other neurological diseases.
The level of α-syn was lower in patients with neurodegenerative diseases than in cognitively normal subjects, but the level of α-syn alone did not distinguish synucleinopathies from tauopathies. An inverse correlation between α-syn and total tau levels was observed ().
PD, DLB patients and controls showed comparable levels of α-syn. AD patients showed significantly lower level of α-syn than the controls (). AD patients with MMSE scores below 20 had significantly lower level of α-syn than AD patients with MMSE scores of 20 or higher ().
The level of α-syn was not different among PD, DLB, AD, and controls. In DLB patients, lower α-syn was related to lower MMSE scores () and worse category fluency ().
The level of α-syn was comparable among PD, MSA, DLB patients and controls. In PD group, the level of α-syn was negatively correlated with age at time of lumber puncture ().
The level of total α-syn was not different between PD, DLB, MSA and control groups. Oligomeric phosphorylated α-syn was significantly high in patients with MSA ().
The level of total α-syn in PD patients was comparable to that of control groups. The level of α-syn oligomer in PD patients was significantly higher than controls ().
Arrows indicate decreased (↓) and comparable (→) levels α-synuclein. Sample numbers are shown in each category. *Erythrocyte counts or haemoglobin levels were considered as a confounding factor. AD: Alzheimer’s disease; DLB: dementia with Lewy bodies; PD: Parkinson’s disease; MSA: multiple system atrophy; α-syn: α-synuclein; MMSE: minimental state examination.