FGF23 and congenital anomaly of kidney and urinary tract: It is interesting to note that we and others have previously shown that higher FGF23 levels have been associated with preserved indices of mineralization.(17, 31) Although skeletal mineralization is not currently assessed by any of the available imaging techniques, a combination of serum alkaline phosphatase and FGF23 levels may potentially serve as more specific biomarkers of skeletal defects in CAKUT patients.