For example, it might be indicated to suffer from PD in the patients when FGG exists obviously or Apo A-IV ∼26 kDa fragment disappears in serum, or the ratio of ITI-H4 subunits 120 kDa and 35 kDa is larger than 3.20 (95% confidence interval for control group was 0.86 to 1.14 and for PD group was 3.23 to 4.47, respectively). The gene discussed is ITIH4; the disease is Parkinson disease.