FGF23 and hydrops fetalis: Increased serum FGF-23 levels have also been associated with increased incidence of AF (Seiler et al., 2011; Mathew et al., 2014), LVH (Faul et al., 2011), HF (Ix et al., 2012), and mortality (Isakova et al., 2011) in a concentration-dependent manner in renal patients.