When the list of proteins is sorted by SD value in ascending order, TPD52L2, EIF4B, CD63, MCEE, VAPA, LUC7L2, PCNP, MT1F, NIPBL, SERF2, SDC4, and so on were the most upregulated proteins in PD, whereas MRPL28, hCG_1984214, MRPL37, MRPS9, RTL8C, MRPS24, TIMM23B, MRPL3, MRPL38, LNPEP, and so on were the most downregulated proteins in PD. This evidence concerns the gene LNPEP and Parkinson disease.