At time 0, CSF NGAL, CSF IFNγ, CSF CRP, and serum CRP co-varied with α-synuclein, Aβ40, and Aβ42 in a disease-dependent manner (Fig. 3): PD subjects demonstrated a relationship between CSF NGAL and CSF α-synuclein (Fig. 3a) as well as CSF NGAL and CSF Aβ40 (b), while HC subjects did not. The gene discussed is IFNG; the disease is Parkinson disease.