Non-microbiological multimodal analysis (i.e., elevated serum CRP or ESR or elevated synovial WBC count or elevated PMN percentage and/or positive histology) established the diagnosis in 127 of 131 (96.9%) cases, whereas microbiological diagnostic evaluation (≥2 positive identical cultures and/or positive sequencing results) confirmed PJI pathogens in 116 of 131 (88.5%) cases. The gene discussed is ESR1; the disease is juvenile polyposis syndrome.