Unexpectedly, when we focused on early CKD patients (stages 1, 2 and 3), univariate analysis indicated that serum FGF23 levels did not correlate significantly with renal α-KL levels, and multiple regression analysis clearly showed that eGFR and serum Pi were significant independent determinants of serum FGF23 levels, but renal α-KL was not. The gene discussed is FGF23; the disease is chronic kidney disease.