The 5 spots with increased expression in PD patients were identified as fibrinogen gamma chain (FGG) (spots 209, 213, 214, and 390) and haptoglobin (spot 14), and the 8 spots with decreased expression relative to the normal subjects were identified as prothrombin (spots 429 and 277), inter-alpha-trypsin inhibitor heavy chain H4 (ITI-H4) (spots 422 and 393), apolipoprotein A-I (spots 278 and 41), and apolipoprotein A-IV (Apo A-IV) (spots 268 and 266). The gene discussed is APOA4; the disease is Parkinson disease.