Table 7. . Table of candidate protein biomarkers for Parkinson's disease.
| Marker | Biofluid | >100/group | Replicated | Synopsis of result | Study (year) | Ref. |
|---|---|---|---|---|---|---|
| EGF |
Plasma/serum |
Y |
Y |
Lower EGF predicts cognitive decline, but effect is modest |
Chen-Plotkin et al. (2011) Pellecchia et al. (2013) Lim et al. (2016) |
[106] [107] [108] |
| Aβ, PTau, TTau |
CSF |
Y |
Y |
Lower Aβ and higher P-tau may predict cognitive decline |
Siderowf et al. (2010) Zhang et al. (2013) |
[109] [110] |
| Total ASyn |
CSF |
Y |
Y |
Lower α-synuclein predicts better preservation of cognitive function |
Stewart et al. (2014) |
[111] |
| ApoA1 |
Plasma/serum |
Y |
Y |
Lower ApoA1 levels correlate with earlier age at onset and greater disease severity |
Qiang et al. (2013) Swanson et al. (2015) |
[112] [113] |
| Vit D |
Plasma/serum |
Y |
Y |
More Vit D insufficiency in PD vs controls Lower Vit D correlates with increased risk of developing PD |
Evatt et al. (2008) Knekt et al. (2010) Ding et al. (2013) |
[114] [115] [116] |
| Urate |
Plasma/serum |
Y |
Y |
Higher urate possibly protective, especially in men. In trials |
Schwarzschild et al. (2008) Ascherio et al. (2009) |
[117] [118] |
| Panel of 21 proteins |
Serum |
Y |
N |
21-protein panel differentiates PD vs AD vs control. High accuracy |
O'Bryant et al. (2014) |
[119] |
| Panel of 7 proteins (ASyn, DJ1, PTau, TTau, Aβ, Flt3Ligand, fractalkine) |
CSF |
N |
N |
PD vs control sens 92%/spec 60% PD vs MSA sens 99%/spec 90% PD vs AD sens 92%/spec 84% |
Shi et al. (2011) |
[120] |
| Panel of 6 proteins/peptides (SPP1, LRP1, CSF1R, EPH4, TIMP1, APLP1) |
CSF |
N |
N |
AUC 0.85 differentiating PD vs controls |
Shi et al. (2015) |
[121] |
| AD-derived markers (CSF Aβ, PTau, TTau, MRI, APOE genotype) | multimodal | N | N | AUC 0.87 differentiating PD with normal cognition vs PD with dementia | Berlyand et al. (2016) | [122] |
Shaded lines indicate candidates tested in larger samples with replication (results are more certain). Other markers, for which results are less certain, are included if the reported effect size is large. List represents markers with high certainty or potentially high effect sizes developed by PDBP investigators; it does not presume to represent the entire literature.
CSF: Cerebrospinal fluid.