However, plasma levels of α-synuclein are strongly influenced by red blood cell (RBC) contamination and hemolysis because RBCs are the major source (>99%) of α-synuclein in blood [24], contributing to the conflicting results for serum or plasma quantities of total α-synuclein in patients with PD compared to controls [9,10,11]. The gene discussed is SNCA; the disease is Parkinson disease.