FGF23 and Hypocalcemia: Serum FGF-23 concentrations have not been reported for ADH2 patients, and our finding of low FGF-23 values in Dsk7/Dsk7 mice was most likely a consequence of the hypocalcemia, which has been previously shown to reduce circulating FGF-23 concentrations in parathyroidectomized rats and in rats with hypocalcemia due to dietary calcium restriction (29).