Posavi et al. (2019) used SOMAScan to detect 1,129 proteins in the serum of PD patients and normal people. They found that compared with people without PD, the levels of four proteins in the serum of PD patients showed the stable difference, namely BSP, OMD, ACY1, and GHR. They also compared the change in serum protein levels in PD patients longitudinally and showed that these proteins could be used to predict disease progression (Posavi et al., 2019). This evidence concerns the gene GHR and Parkinson disease.