After adjusting for age, gender, and body mass index (BMI), median circulating FGF21 level in end-stage CKD patients (1447.9±146.5 pg/ml) was 10-fold higher compared with normal subjects (147.3±12.25 pg/ml; P<0.0001); and about 3.5-fold higher compared with the early-stage CKD patients (402.9±35.0 pg/ml; P<0.0001), and about 1.5-fold higher compared with the middle-stage CKD patients (845.8±238.7 pg/ml; P<0.0001; Figure 1). The gene discussed is FGF21; the disease is chronic kidney disease.