In chronic periodontitis, 7 biomarkers exclusive to the pathology are suggested, but only 2, a chemokine (C-C motif) ligand 13 (Q99616), 4.97x upregulated in disease samples, and thymidine phosphorylase (P19971), 3.7x downregulated in disease samples, fulfill both requisites proposed for a biomarker, to be exclusive of the disease state and to have an up/down amount ≥3x. Here, TYMP is linked to periodontitis.