SNCA and Parkinson disease: On the other hand, a recent study estimated the levels of total α-synuclein, o-α-syn, total-tau, phosphorylated tau, α-synuclein-amyloid β42 complex, and α-synuclein-tau complex in red blood cells of PD patients; decreased total α-synuclein and increased levels of o-α-syn, phosphorylated-tau, and α-synuclein-amyloid β42 complex were observed in PD subjects with respect to controls (Daniele et al., 2018).