FGF23 and hypophosphatemia: Biological parameters were vastly similar, with preserved renal function (eGFR 109(93–111) mL/min/1.73 m2), hypophosphatemia (median − 1.9(-3.4;-1.7) SDS for age), elevated FGF-23 (98(84–117) RU/mL, normal range 21–91 RU/mL) with hypocalciuria and low TmP/GFR.