These terms included cornification, antimicrobial humoral response, digestion, collagen-containing extracellular matrix, cornified envelope, neuronal cell body, serine-type endopeptidase activity, receptor-ligand activity, channel activity, neuroactive ligand-receptor interaction, PPAR signaling pathway and nicotine addiction, etc. The detailed results of functional annotation are provided in Supplementary Table S3. The gene discussed is PPARA; the disease is nicotine dependence.