Nevertheless, values of FGF-23 by these different assays are well correlated [20, 50] and both high intact FGF-23 and C-terminal FGF-23 concentrations are consistently and independently associated with increased mortality risk and poor outcome in patients with CKD; thus, it may be considered desirable to lower circulating FGF-23 levels. The gene discussed is FGF23; the disease is chronic kidney disease.