The established 3-dimensional model was based on the linear discriminant function, as shown below, to illustrate the 3D scatter plot of the samples and classify the patients with normal controls, PD-NC, PD-MCI, and PDD (Figure 7).f = −0.00489Tau−0.156621pTau + 0.006844 Aβ40 + 0.027807 Aβ42 − 0.57530 log(α-synuclein)(3). The gene discussed is SNCA; the disease is Parkinson disease.