Several biomarkers have been studied in recent years to improve the accuracy of diagnosing PJI, such as C-reactive protein (CRP) [6], α-defensin [7], leukocyte esterase [8], interleukin-6 (IL-6) [9], vascular endothelial growth factor [10], and granulocyte colony-stimulating factor [11], but the overall sensitivity (77–97%) and specificity (86–96%) remain inadequate [12]. The gene discussed is CRP; the disease is juvenile polyposis syndrome.