The classification accuracy (area under the ROC curve, AUC) of these three key genes (DDX17, DACH1, TCF21) was 0.828, 0.825 and 0.981 in the discovery cohort and 0.885, 0.838 and 0.949 in the validation cohort, respectively, showing strong ability to discriminate between CKD and healthy individuals. The gene discussed is TCF21; the disease is chronic kidney disease.