Moreover, pharmacological activation of FGFR1 by monoclonal antibodies in adult mice led to increased serum FGF23 levels and mild hypophosphatemia, and the same monoclonal antibody in cultured rat calvarial osteoblasts induced Fgf23 mRNA expression and protein secretion into the culture medium (24). The gene discussed is FGF23; the disease is hypophosphatemia.