Urine Klotho and the urine Klotho/creatinine ratio were decreased significantly in pre-renal versus intrinsic AKI patients (urine Klotho, 15.44±17.11 vs. 30.26±47.26 ng/g, P = 0.015; urine Klotho/creatinine ratio, 173.54±292.26 vs. 381.35±630.40 ng/g, P = 0.001; Fig 6(a)). The gene discussed is KL; the disease is acute kidney injury.