Animal and human studies have shown that specific conditions, such as treatment with active vitamin D (Kolek et al., 2005; Yamamoto et al., 2010; Hansen et al., 2012; Sprague et al., 2015), phosphate overload (Hori et al., 2016; Perwad et al., 2005; Antoniucci et al., 2006; Ferrari et al., 2005), and uremia (Stubbs et al., 2007), upregulate FGF23 transcription in bone and elevate circulating FGF23 concentrations. The gene discussed is FGF23; the disease is uremia.