As for the top 20 canonical pathways mutually expressed in the pathogenesis of NF1, periodontitis, and sicca syndrome, which were ordered based on the sum of z scores, fibrosis signaling pathway was highly expressed in the three disease groups when compared to healthy donors, with Z scores being 3.70 for NF1, 4.54 for periodontitis, and 3.5 for sicca syndrome, and significant − log10(P) values being 11.28 for NF1, 10.66 for periodontitis, and 3.30 for sicca syndrome, respectively. The gene discussed is NF1; the disease is periodontitis.