FGF7 and hyperphosphatemia: Indeed, a recent study in patients with pediatric HPP confirmed the presence of hyperphosphatemia, which was not correlated with the disease severity, the elevated TmP/GFR along with inappropriately normal FGF23 and secreted Frizzled Related Protein 4 (sFRP4) levels, and low levels of fibroblast growth factor 7 (FGF7) [12].