KEGG enrichment revealed that the up-regulated proteins are mainly involved in pathways associated with immunodeficient diseases and/or related protein processing and biosynthesis (Fig. 2D); the down-regulated proteins are mainly involved in energy metabolism, such as cyclochrome P450 related metabolism, chemical carcinogenesis, stereoid hormone biosynthesis, fatty acid metabolism, tryptophan metabolism and/or PPAR signaling pathway (Fig. 2E). The gene discussed is PPARA; the disease is immunodeficiency disease.