However, prospective and cross-sectional clinical studies have shown that circulating FGF23 is positively and dose dependently associated with CKD progression, cardiovascular risk factors such as left ventricular hypertrophy, vascular calcifications, and mortality in CKD patients (Juppner et al, 2010; Faul et al, 2011), suggesting that FGF23 may have additional biological functions which cannot be explained by the known effects of FGF23 on mineral metabolism. This evidence concerns the gene FGF23 and chronic kidney disease.